Existing model tests for reinforcing loess slopes with stabilizing piles are often challenged by simulation inaccuracies in lateral loading modes and scaling. Addressing these concerns, this study conducts model tests and numerical simulations to scrutinize the damage characteristics of concrete piles in two varying loess slope conditions under non-uniform lateral loading. The tests were designed to strictly maintain the similarity ratio of the concrete piles. The results reveal a no table 20% reduction in lateral bearing capacity due to the penetration of a potential sliding surface, exacerbating the stress on the piles. Furthermore, compared to uniform loess slopes, the presence of a sliding surface leads to a 38.4% increase in the height of the stress concentration point, resulting in earlier crack formation in the piles. These findings offer substantial theoretical and practical insights, highlighting the critical need for accurate model simulation in slope stabilization research and providing a basis for improving engineering practices.
{"title":"Fracture Disaster Assessment of Model Concrete Piles in Loess Slope Engineering under Non-Uniform Lateral Loading","authors":"Weishi Bai, Rongjian Li, Guoqiang Lin, Rongjin Li, Hao Jiang, Laizhu Wang, Chaoneng Bai","doi":"10.3390/buildings14010173","DOIUrl":"https://doi.org/10.3390/buildings14010173","url":null,"abstract":"Existing model tests for reinforcing loess slopes with stabilizing piles are often challenged by simulation inaccuracies in lateral loading modes and scaling. Addressing these concerns, this study conducts model tests and numerical simulations to scrutinize the damage characteristics of concrete piles in two varying loess slope conditions under non-uniform lateral loading. The tests were designed to strictly maintain the similarity ratio of the concrete piles. The results reveal a no table 20% reduction in lateral bearing capacity due to the penetration of a potential sliding surface, exacerbating the stress on the piles. Furthermore, compared to uniform loess slopes, the presence of a sliding surface leads to a 38.4% increase in the height of the stress concentration point, resulting in earlier crack formation in the piles. These findings offer substantial theoretical and practical insights, highlighting the critical need for accurate model simulation in slope stabilization research and providing a basis for improving engineering practices.","PeriodicalId":48546,"journal":{"name":"Buildings","volume":"37 11","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139441383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-10DOI: 10.3390/buildings14010171
Huy Q Nguyen, Hoe-Jin Kim, Nam-Hyoung Lim, Yun-Suk Kang, Jung J. Kim
Railway derailments present a safety hazard, carrying the potential for severe consequences for both human lives and the economy. Implementing derailment containment provisions (DCPs) near the track centerline is essential for mitigating risks in operating high-speed rail (HSR) while providing significant advantages for the large-scale upgrade of existing railway infrastructure. Therefore, this paper investigated the feasibility of a DCP system made of steel through quasi-static experiments, aiming to enhance safety in HSR operations. Initially, single anchor tests were conducted to assess its capacity to withstand applied loads, prevent the pullout of steel anchors, and avoid the local rotation of the steel frame. Then, full-scale steel DCP systems were manufactured and tested for quasi-static load at different locations, including the mid-anchor, the mid-span, and the end-anchor. The relationship between applied load and displacement, along with the initial stiffness of the DCP specimens, was discussed. The findings revealed that the single anchor can withstand an applied load of up to 197.9 kN. The DCP specimen maintained structural integrity at the 207 kN target load under all load scenarios, showing a maximum displacement of 8.93 mm in the case of applied load at mid-span. Furthermore, the initial stiffness of the DCP systems was 1.77 to 2.55 times greater than that of a single anchor, validating a force-bearing coordination mechanism among neighboring anchors and the substantial impact of the applied load positions on their stiffness.
{"title":"Feasibility Study of Steel Derailment Containment Provisions through Quasi-Static Experiments","authors":"Huy Q Nguyen, Hoe-Jin Kim, Nam-Hyoung Lim, Yun-Suk Kang, Jung J. Kim","doi":"10.3390/buildings14010171","DOIUrl":"https://doi.org/10.3390/buildings14010171","url":null,"abstract":"Railway derailments present a safety hazard, carrying the potential for severe consequences for both human lives and the economy. Implementing derailment containment provisions (DCPs) near the track centerline is essential for mitigating risks in operating high-speed rail (HSR) while providing significant advantages for the large-scale upgrade of existing railway infrastructure. Therefore, this paper investigated the feasibility of a DCP system made of steel through quasi-static experiments, aiming to enhance safety in HSR operations. Initially, single anchor tests were conducted to assess its capacity to withstand applied loads, prevent the pullout of steel anchors, and avoid the local rotation of the steel frame. Then, full-scale steel DCP systems were manufactured and tested for quasi-static load at different locations, including the mid-anchor, the mid-span, and the end-anchor. The relationship between applied load and displacement, along with the initial stiffness of the DCP specimens, was discussed. The findings revealed that the single anchor can withstand an applied load of up to 197.9 kN. The DCP specimen maintained structural integrity at the 207 kN target load under all load scenarios, showing a maximum displacement of 8.93 mm in the case of applied load at mid-span. Furthermore, the initial stiffness of the DCP systems was 1.77 to 2.55 times greater than that of a single anchor, validating a force-bearing coordination mechanism among neighboring anchors and the substantial impact of the applied load positions on their stiffness.","PeriodicalId":48546,"journal":{"name":"Buildings","volume":"84 16","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139440747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-10DOI: 10.3390/buildings14010172
Andrey P. Pustovgar, Yury R. Krivoborodov, A. Adamtsevich, A. Elenova, Kseniya A. Butenko, Dmitrii V. Kramerov, Anton M. Bugaev
This research work attempts to reveal the mechanism of alkali corrosion in cement composites in the presence of plasticizers based on polycarboxylates (PCE), naphtha-lene-formaldehydes (SPNF), and lignosulfonates by maintaining a high pH of the liquid phase and additionally containing monovalent alkali earth metals in cement stone, as well as stopping this process by introducing an active mineral additive. ASR is studied by changing the relative strain with time according to ASTM C-1260. Deformation changes were confirmed by SEM and RFA studies of hydration products and ASR in the microstructure. Separate use of PCE plasticizers in the cement composition increases deformation by 50% to the 56th day; the use of SPNF increases deformation by 10% compared with the additive-free composition. The use of PLS reduces the relative deformation by 25%. The introduction of silica fume into cementitious composites containing plasticizers actually stops ASR only for a short time. A reduction in deformation during MC use together with plasticizer based on naphthalene sulfonate and polycarboxylate occurs only when the dosage of MS is increased to 20–30%; at a lower dosage, the effect is negative, which also affects the phase composition of the composites. The introduction of MC increases the value of the relative deformation compared with plasticizer compositions based only on PLS. SEM studies have detected microcracks and dense fine-crystalline silicate gel, which cause deformation changes in cement composite samples. Research has shown that concrete modified with SPNF and PCE at the maximum dosage of MC (30%) has minimal deformation rates and can be used to select optimal concrete compositions. The results of this study could help to minimize risks, prevent unacceptable expansion, and ensure the high quality of concrete and concrete products during their use as part of various nature-modifying additives.
这项研究工作试图揭示水泥复合材料在聚羧酸盐（PCE）、石脑油-烯-甲醛（SPNF）和木质素磺酸盐等增塑剂存在的情况下发生碱腐蚀的机理，具体方法是在水泥石中保持较高的液相 pH 值并额外添加单价碱土金属，以及通过引入活性矿物添加剂来阻止这一过程。根据 ASTM C-1260 标准，通过随时间变化的相对应变来研究 ASR。通过对微观结构中的水化产物和 ASR 进行 SEM 和 RFA 研究，证实了变形的变化。在水泥成分中单独使用 PCE 增塑剂会使第 56 天的变形量增加 50%；与不含添加剂的成分相比，使用 SPNF 会使变形量增加 10%。使用 PLS 可使相对变形量减少 25%。在含有增塑剂的水泥基复合材料中引入硅灰实际上只能在短时间内阻止 ASR。在 MC 与基于萘磺酸盐和聚羧酸盐的增塑剂一起使用时，只有当 MS 的用量增加到 20-30% 时才会减少变形；用量较低时，效果为负，这也会影响复合材料的相组成。与仅基于 PLS 的增塑剂成分相比，MC 的引入增加了相对变形值。扫描电子显微镜研究发现，微裂缝和致密的细晶硅酸盐凝胶会导致水泥复合材料样品发生变形变化。研究表明，在最大 MC 用量（30%）下使用 SPNF 和 PCE 改性的混凝土变形率最小，可用于选择最佳混凝土成分。这项研究的结果有助于最大限度地降低风险，防止不可接受的膨胀，并确保混凝土和混凝土产品在作为各种改性添加剂的一部分使用时的高质量。
{"title":"The Impact of Plasticizers on the Nature of the Alkali-Silicate Corrosion in Cement Composites","authors":"Andrey P. Pustovgar, Yury R. Krivoborodov, A. Adamtsevich, A. Elenova, Kseniya A. Butenko, Dmitrii V. Kramerov, Anton M. Bugaev","doi":"10.3390/buildings14010172","DOIUrl":"https://doi.org/10.3390/buildings14010172","url":null,"abstract":"This research work attempts to reveal the mechanism of alkali corrosion in cement composites in the presence of plasticizers based on polycarboxylates (PCE), naphtha-lene-formaldehydes (SPNF), and lignosulfonates by maintaining a high pH of the liquid phase and additionally containing monovalent alkali earth metals in cement stone, as well as stopping this process by introducing an active mineral additive. ASR is studied by changing the relative strain with time according to ASTM C-1260. Deformation changes were confirmed by SEM and RFA studies of hydration products and ASR in the microstructure. Separate use of PCE plasticizers in the cement composition increases deformation by 50% to the 56th day; the use of SPNF increases deformation by 10% compared with the additive-free composition. The use of PLS reduces the relative deformation by 25%. The introduction of silica fume into cementitious composites containing plasticizers actually stops ASR only for a short time. A reduction in deformation during MC use together with plasticizer based on naphthalene sulfonate and polycarboxylate occurs only when the dosage of MS is increased to 20–30%; at a lower dosage, the effect is negative, which also affects the phase composition of the composites. The introduction of MC increases the value of the relative deformation compared with plasticizer compositions based only on PLS. SEM studies have detected microcracks and dense fine-crystalline silicate gel, which cause deformation changes in cement composite samples. Research has shown that concrete modified with SPNF and PCE at the maximum dosage of MC (30%) has minimal deformation rates and can be used to select optimal concrete compositions. The results of this study could help to minimize risks, prevent unacceptable expansion, and ensure the high quality of concrete and concrete products during their use as part of various nature-modifying additives.","PeriodicalId":48546,"journal":{"name":"Buildings","volume":"41 11","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139441149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-09DOI: 10.3390/buildings14010166
Alessandro Gandolfi, N. Pingaro, Gabriele Milani
This paper presents a new method to model the nonlinear behavior of double-curvature masonry structures, possibly reinforced by composite materials, by means of conventional elasto-plastic analyses. The method is meant to be used in professional design, especially for assessment and retrofitting purposes, based on the exploitation of the simplest nonlinear finite elements available in commercial software, namely, trusses with elasto-fragile and elasto-ductile behavior (Cutoff Bars, according for instance to the definition provided by Strand7 R3.1.3a). Numerical static nonlinear analyses are carried out by considering elastic hexahedral elements for bricks and by lumping nonlinearities on joints. These are assumed, in turn, to be elastic–brittle and elastic–plastic by using 1D elements, namely, Point Contacts, under the No-Tension Material hypothesis, and Cutoff Bars, respectively, assigning a small tensile resistance to the material. The reinforcement, realized with FRP hooping strips, is successfully modeled in a similar fashion, i.e., by applying perfectly bonded elastic–plastic Cutoff Bars at the extrados of the dome, where debonding is accounted for in a conventional way, limiting the tensile strength according to Italian Standards’ indications. The procedure is validated against benchmark models with the same geometry, using experimental data and more refined structural model results for comparison. After an in-depth analysis of the obtained results, in terms of capacity curves, the robustness and accuracy of the proposed approach are assessed.
{"title":"Simple Nonlinear Numerical Modeling for Unreinforced and FRP-Reinforced Masonry Domes","authors":"Alessandro Gandolfi, N. Pingaro, Gabriele Milani","doi":"10.3390/buildings14010166","DOIUrl":"https://doi.org/10.3390/buildings14010166","url":null,"abstract":"This paper presents a new method to model the nonlinear behavior of double-curvature masonry structures, possibly reinforced by composite materials, by means of conventional elasto-plastic analyses. The method is meant to be used in professional design, especially for assessment and retrofitting purposes, based on the exploitation of the simplest nonlinear finite elements available in commercial software, namely, trusses with elasto-fragile and elasto-ductile behavior (Cutoff Bars, according for instance to the definition provided by Strand7 R3.1.3a). Numerical static nonlinear analyses are carried out by considering elastic hexahedral elements for bricks and by lumping nonlinearities on joints. These are assumed, in turn, to be elastic–brittle and elastic–plastic by using 1D elements, namely, Point Contacts, under the No-Tension Material hypothesis, and Cutoff Bars, respectively, assigning a small tensile resistance to the material. The reinforcement, realized with FRP hooping strips, is successfully modeled in a similar fashion, i.e., by applying perfectly bonded elastic–plastic Cutoff Bars at the extrados of the dome, where debonding is accounted for in a conventional way, limiting the tensile strength according to Italian Standards’ indications. The procedure is validated against benchmark models with the same geometry, using experimental data and more refined structural model results for comparison. After an in-depth analysis of the obtained results, in terms of capacity curves, the robustness and accuracy of the proposed approach are assessed.","PeriodicalId":48546,"journal":{"name":"Buildings","volume":"14 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139443248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-09DOI: 10.3390/buildings14010168
Zheng Li, Qiulei Zhang, F. Shi, Jian Wang, Hartmut Pasternak
Nowadays, 3D laser scanning technology is extensively employed in laboratory investigations of steel structural components, providing accurate geometric dimensions to reduce uncertainties caused by indeterminate geometry in experimental results. It is often used in conjunction with the Finite Element (FE) Method and analytical solutions, which are more accurate deterministic operators in the research on steel structures. However, establishing a common methodological framework for transferring or mapping 3D-scanned information into finite element models for complex steel structures with stability and fatigue risks remains an ongoing task. In light of this, this study has developed a 3D scanning platform capable of obtaining accurate geometric dimensions for various types of steel components. Different coordinate systems and point cloud mapping algorithms have been established for different types of components to construct actual finite element models with initial imperfections. The feasibility of the self-developed 3D scanning platform and finite element modelling has been validated through three experimental cases: weld details, steel girders, and cylindrical shells. The research findings demonstrate that the captured point cloud can be automatically processed and corrected using the developed algorithm. The scanned data can then be input into the numerical model using various mapping algorithms tailored to the specific geometric properties of the specimens. The differences between the experimental test results and the simulated results obtained from the 3D-scanned finite element models remain within a small range. The self-developed 3D scanning platform and finite element modelling technique effectively capture the actual dimensions of different steel components, enabling the prediction of their stability and fatigue risks through numerical simulations.
{"title":"Geometric Properties of Steel Components with Stability and Fatigue Risks Using 3D-Laser-Scanning","authors":"Zheng Li, Qiulei Zhang, F. Shi, Jian Wang, Hartmut Pasternak","doi":"10.3390/buildings14010168","DOIUrl":"https://doi.org/10.3390/buildings14010168","url":null,"abstract":"Nowadays, 3D laser scanning technology is extensively employed in laboratory investigations of steel structural components, providing accurate geometric dimensions to reduce uncertainties caused by indeterminate geometry in experimental results. It is often used in conjunction with the Finite Element (FE) Method and analytical solutions, which are more accurate deterministic operators in the research on steel structures. However, establishing a common methodological framework for transferring or mapping 3D-scanned information into finite element models for complex steel structures with stability and fatigue risks remains an ongoing task. In light of this, this study has developed a 3D scanning platform capable of obtaining accurate geometric dimensions for various types of steel components. Different coordinate systems and point cloud mapping algorithms have been established for different types of components to construct actual finite element models with initial imperfections. The feasibility of the self-developed 3D scanning platform and finite element modelling has been validated through three experimental cases: weld details, steel girders, and cylindrical shells. The research findings demonstrate that the captured point cloud can be automatically processed and corrected using the developed algorithm. The scanned data can then be input into the numerical model using various mapping algorithms tailored to the specific geometric properties of the specimens. The differences between the experimental test results and the simulated results obtained from the 3D-scanned finite element models remain within a small range. The self-developed 3D scanning platform and finite element modelling technique effectively capture the actual dimensions of different steel components, enabling the prediction of their stability and fatigue risks through numerical simulations.","PeriodicalId":48546,"journal":{"name":"Buildings","volume":"5 7","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139443818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-09DOI: 10.3390/buildings14010160
Shujun Hu, Shangwen Liu, Sizhi Zeng, Tiefeng Shao
The current specification requires the same limiting values of inelastic rotation and the overstrength factor for shear links with a length ratio less than 1.6. However, recent studies have shown that the mechanical properties of ordinary shear links with a length ratio ranging from 1.0 to 1.6 are obviously different from those of very short shear links with a length ratio less than 1.0. Additionally, shear links made of different steel materials have differences in mechanical properties. Based on Q345 steel, three ordinary shear links with a length ratio of 1.36 were designed to intensively explore the influence of stiffener configurations and spacing on mechanical properties. Under cyclic loading tests, the failure modes, hysteresis curves, skeleton curves, secant stiffness curves and energy dissipation capacities of shear link specimens were recorded. The results show that the overstrength factor and inelastic rotation of specimens SL-1 and SL-2, which had different stiffener configurations, reached 1.59 and 0.10, while those of specimen SL-3, which had wider stiffener spacing, reached 1.48 and 0.07, which showed that varying the stiffener configuration has no obvious effect, while relaxing stiffener spacing can result in severe buckling of the web. Additionally, its bearing capacity, inelastic rotation, secant stiffness and energy dissipation capacity reduced. Hence, the stiffener spacing should satisfy the requirements of the specification and not be too wide. Based on ABAQUS software, finite element models of ordinary shear links proved to be accurately consistent with test specimens in terms of mechanical properties. On this basis, 114 numerical models of ordinary shear links with different length ratios, stiffener spacings, flange-to-web area ratios, flange strengths, web depth-to-thickness ratios and stiffener thicknesses were designed to study the influence on the overstrength factor.
{"title":"Mechanical Properties and Influence Factors of Ordinary Shear Links","authors":"Shujun Hu, Shangwen Liu, Sizhi Zeng, Tiefeng Shao","doi":"10.3390/buildings14010160","DOIUrl":"https://doi.org/10.3390/buildings14010160","url":null,"abstract":"The current specification requires the same limiting values of inelastic rotation and the overstrength factor for shear links with a length ratio less than 1.6. However, recent studies have shown that the mechanical properties of ordinary shear links with a length ratio ranging from 1.0 to 1.6 are obviously different from those of very short shear links with a length ratio less than 1.0. Additionally, shear links made of different steel materials have differences in mechanical properties. Based on Q345 steel, three ordinary shear links with a length ratio of 1.36 were designed to intensively explore the influence of stiffener configurations and spacing on mechanical properties. Under cyclic loading tests, the failure modes, hysteresis curves, skeleton curves, secant stiffness curves and energy dissipation capacities of shear link specimens were recorded. The results show that the overstrength factor and inelastic rotation of specimens SL-1 and SL-2, which had different stiffener configurations, reached 1.59 and 0.10, while those of specimen SL-3, which had wider stiffener spacing, reached 1.48 and 0.07, which showed that varying the stiffener configuration has no obvious effect, while relaxing stiffener spacing can result in severe buckling of the web. Additionally, its bearing capacity, inelastic rotation, secant stiffness and energy dissipation capacity reduced. Hence, the stiffener spacing should satisfy the requirements of the specification and not be too wide. Based on ABAQUS software, finite element models of ordinary shear links proved to be accurately consistent with test specimens in terms of mechanical properties. On this basis, 114 numerical models of ordinary shear links with different length ratios, stiffener spacings, flange-to-web area ratios, flange strengths, web depth-to-thickness ratios and stiffener thicknesses were designed to study the influence on the overstrength factor.","PeriodicalId":48546,"journal":{"name":"Buildings","volume":"48 2","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139444901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-09DOI: 10.3390/buildings14010161
Karan Moolchandani, Abhay Sharma, D. Kishan
In addressing the dual challenges of sustainable waste management and environmental conservation in the construction industry, particularly the disposal of waste tire crumb rubber (CR) and the demand for eco-friendly building materials, this study explores a novel solution. It examines the sustainable incorporation of waste tire crumb rubber and mineral additions—namely silica fume (SF), marble slurry powder (MSP), and fly ash (FA)—as partial substitutes for natural fine aggregates and cement in concrete. Through comprehensive testing of seventeen concrete samples, the study reveals that the specific mix of R10S5M10F15 that contained 10% crumb rubber as replacement of fine aggregates, and 5% silica fume, 10% marble slurry powder and 15% fly ash as replacements of cement, not only achieves compressive and split tensile strength comparable to the control mix, while the 90 days flexural strength was improved by 4.48%; credited to SF’s pozzolanic action and the filler effects of MSP and FA, but also that the inclusion of CR, while reducing compressive strength due to material variations, enhances ductility and improves resistance to sulfate and acid attacks, despite increasing water absorption. The primary goal of this research is to investigate the feasibility and effectiveness of using waste materials in concrete to foster more sustainable construction practices. The objectives include a detailed assessment of the mechanical properties and durability of concrete incorporating these waste materials, aiming to determine the optimal mix proportions for their effective utilization. This study’s novelty lies in its detailed analysis of the synergistic effects of combining CR, SF, MSP, and FA in concrete, contributing to the field by offering a sustainable alternative approach to traditional concrete formulations and highlighting the delicate balance required for optimized concrete performance.
为应对建筑行业可持续废物管理和环境保护的双重挑战，特别是废轮胎屑橡胶（CR）的处置和对环保建筑材料的需求，本研究探索了一种新的解决方案。该研究探讨了废轮胎碎屑橡胶和矿物添加剂（即硅灰（SF）、大理石浆粉（MSP）和粉煤灰（FA））在混凝土中部分替代天然细骨料和水泥的可持续掺入。通过对十七个混凝土样品的综合测试，研究发现，含有 10%碎石橡胶作为细骨料替代物，5%硅灰、10%大理石浆粉和 15%粉煤灰作为水泥替代物的 R10S5M10F15 特定混合料，不仅抗压强度和劈裂拉伸强度与对照混合料相当，而且 90 天抗弯强度提高了 4.48% ；这归功于 SF 的水青作用以及 MSP 和 FA 的填料效应，而且，加入 CR 虽然会因材料变化而降低抗压强度，但会增强延展性并提高抗硫酸盐和酸侵蚀的能力，尽管吸水率会增加。这项研究的主要目标是调查在混凝土中使用废料的可行性和有效性，以促进更可持续的建筑实践。目标包括详细评估掺入这些废料的混凝土的机械性能和耐久性，旨在确定有效利用这些废料的最佳混合比例。这项研究的新颖之处在于详细分析了混凝土中 CR、SF、MSP 和 FA 的协同效应，为该领域提供了传统混凝土配方的可持续替代方法，并强调了优化混凝土性能所需的微妙平衡。
{"title":"Enhancing Concrete Performance with Crumb Rubber and Waste Materials: A Study on Mechanical and Durability Properties","authors":"Karan Moolchandani, Abhay Sharma, D. Kishan","doi":"10.3390/buildings14010161","DOIUrl":"https://doi.org/10.3390/buildings14010161","url":null,"abstract":"In addressing the dual challenges of sustainable waste management and environmental conservation in the construction industry, particularly the disposal of waste tire crumb rubber (CR) and the demand for eco-friendly building materials, this study explores a novel solution. It examines the sustainable incorporation of waste tire crumb rubber and mineral additions—namely silica fume (SF), marble slurry powder (MSP), and fly ash (FA)—as partial substitutes for natural fine aggregates and cement in concrete. Through comprehensive testing of seventeen concrete samples, the study reveals that the specific mix of R10S5M10F15 that contained 10% crumb rubber as replacement of fine aggregates, and 5% silica fume, 10% marble slurry powder and 15% fly ash as replacements of cement, not only achieves compressive and split tensile strength comparable to the control mix, while the 90 days flexural strength was improved by 4.48%; credited to SF’s pozzolanic action and the filler effects of MSP and FA, but also that the inclusion of CR, while reducing compressive strength due to material variations, enhances ductility and improves resistance to sulfate and acid attacks, despite increasing water absorption. The primary goal of this research is to investigate the feasibility and effectiveness of using waste materials in concrete to foster more sustainable construction practices. The objectives include a detailed assessment of the mechanical properties and durability of concrete incorporating these waste materials, aiming to determine the optimal mix proportions for their effective utilization. This study’s novelty lies in its detailed analysis of the synergistic effects of combining CR, SF, MSP, and FA in concrete, contributing to the field by offering a sustainable alternative approach to traditional concrete formulations and highlighting the delicate balance required for optimized concrete performance.","PeriodicalId":48546,"journal":{"name":"Buildings","volume":"54 7","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139441957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-09DOI: 10.3390/buildings14010163
Yi Qian, Chuyue Huang, Beilin Han, Fan Cheng, Shengqiang Qiu, Hongyang Deng, Xiang Duan, Hengbin Zheng, Zhiwei Liu, Jie Wu
Bolted connections have become the most widely used connection method in steel structures. Over the long-term service of the bolts, loosening damage and other defects will inevitably occur due to various factors. To ensure the stability of bolted connections, an efficient and precise method for identifying loosened bolts in a given structure is proposed based on computer vision technology. The main idea of this method is to combine deep learning with image processing techniques to recognize and label the loosening angle from bolt connection images. A rectangular steel plate was taken as the test research object, and three grade 4.8 ordinary bolts were selected for study. The analysis was conducted under two conditions: manual loosening and simulated loosening. The results showed that the method proposed in this article could accurately locate the position of the bolts and identify the loosening angle, with an error value of about ±0.1°, which proves the accuracy and feasibility of this method, meeting the needs of structural health monitoring.
{"title":"Quantitative Analysis of Bolt Loosening Angle Based on Deep Learning","authors":"Yi Qian, Chuyue Huang, Beilin Han, Fan Cheng, Shengqiang Qiu, Hongyang Deng, Xiang Duan, Hengbin Zheng, Zhiwei Liu, Jie Wu","doi":"10.3390/buildings14010163","DOIUrl":"https://doi.org/10.3390/buildings14010163","url":null,"abstract":"Bolted connections have become the most widely used connection method in steel structures. Over the long-term service of the bolts, loosening damage and other defects will inevitably occur due to various factors. To ensure the stability of bolted connections, an efficient and precise method for identifying loosened bolts in a given structure is proposed based on computer vision technology. The main idea of this method is to combine deep learning with image processing techniques to recognize and label the loosening angle from bolt connection images. A rectangular steel plate was taken as the test research object, and three grade 4.8 ordinary bolts were selected for study. The analysis was conducted under two conditions: manual loosening and simulated loosening. The results showed that the method proposed in this article could accurately locate the position of the bolts and identify the loosening angle, with an error value of about ±0.1°, which proves the accuracy and feasibility of this method, meeting the needs of structural health monitoring.","PeriodicalId":48546,"journal":{"name":"Buildings","volume":"18 6","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139443781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-09DOI: 10.3390/buildings14010162
Meng Wu, Bin Wang, Qingxuan Shi, Wenzhe Cai
To investigate the effects of parameters on the seismic performance of slender T-shaped RC walls subjected to a biaxial seismic action, a numerical model was established using a fiber-based cross-section and displacement-based beam–column element. The axial load ratio, shear span ratio, flange width to web height ratio, concrete strength grade, stirrup ratio, and longitudinal reinforcement ratio were selected for the parametric study, and the effects of these parameters on the performance degradation under biaxial loading were investigated. Furthermore, a sensitivity analysis of various parameters for the decrease was conducted. The results showed that the bearing and deformation capacities under biaxial loading were both decreased, and the total energy consumption was greater than that under uniaxial loading. The impacts of different parameters and loading paths on the decrease extent were significantly different, and the overall reduction was greater in the flange direction than in the web direction. Under the square loading path, the T-shaped wall had the greatest reduction in its seismic performance, followed by the eight-shaped and cruciform loading paths. The changes in the axial load ratio, shear span ratio, and concrete strength significantly affected the performance degradation under biaxial loading. Accordingly, it is recommended to reasonably consider the values of these three parameters in a multidimensional seismic design to maintain safety redundancy.
为了研究参数对细长 T 型 RC 墙在双轴地震作用下抗震性能的影响，采用基于纤维的截面和基于位移的梁柱元素建立了数值模型。参数研究选取了轴荷载比、剪跨比、翼缘宽度与腹板高度比、混凝土强度等级、箍筋率和纵向配筋率，并研究了这些参数对双轴荷载作用下性能退化的影响。此外，还对各种参数的下降进行了敏感性分析。结果表明，双轴加载下的承载能力和变形能力均有所下降，总能耗大于单轴加载下的能耗。不同参数和加载路径对减小程度的影响存在显著差异，且翼缘方向的总体减小程度大于腹板方向。在方形加载路径下，T 型墙的抗震性能降低幅度最大，其次是八字形和十字形加载路径。轴向荷载比、剪跨比和混凝土强度的变化对双轴荷载下的性能降低有显著影响。因此，建议在多维抗震设计中合理考虑这三个参数的值，以保持安全冗余。
{"title":"Parametric Study on Seismic Performance of Slender T-Shaped RC Walls Subjected to Biaxial Loading","authors":"Meng Wu, Bin Wang, Qingxuan Shi, Wenzhe Cai","doi":"10.3390/buildings14010162","DOIUrl":"https://doi.org/10.3390/buildings14010162","url":null,"abstract":"To investigate the effects of parameters on the seismic performance of slender T-shaped RC walls subjected to a biaxial seismic action, a numerical model was established using a fiber-based cross-section and displacement-based beam–column element. The axial load ratio, shear span ratio, flange width to web height ratio, concrete strength grade, stirrup ratio, and longitudinal reinforcement ratio were selected for the parametric study, and the effects of these parameters on the performance degradation under biaxial loading were investigated. Furthermore, a sensitivity analysis of various parameters for the decrease was conducted. The results showed that the bearing and deformation capacities under biaxial loading were both decreased, and the total energy consumption was greater than that under uniaxial loading. The impacts of different parameters and loading paths on the decrease extent were significantly different, and the overall reduction was greater in the flange direction than in the web direction. Under the square loading path, the T-shaped wall had the greatest reduction in its seismic performance, followed by the eight-shaped and cruciform loading paths. The changes in the axial load ratio, shear span ratio, and concrete strength significantly affected the performance degradation under biaxial loading. Accordingly, it is recommended to reasonably consider the values of these three parameters in a multidimensional seismic design to maintain safety redundancy.","PeriodicalId":48546,"journal":{"name":"Buildings","volume":"20 8","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139443724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Using waste plastics in asphalt mixtures could be an exploratory way to dispose of waste plastics. This study aims to investigate the microscopic properties between asphalt and polyethylene (PE) at an extraordinary dosage of 20 wt.%. Various types of PE with different degrees of polymerization (DP) and structural configurations were considered. Molecular dynamics simulations were used to calculate the mechanical parameters, free volume ratio (FVR), and Flory–Huggins parameter of the resulting PE-modified asphalt (PEA). Two types of PEA were made and characterized by fluorescence microscopy. The simulation results indicate that the addition of PE reduces the density of modified asphalt by less than 5%, and a higher density of PEA is associated with a lower FVR. When the FVR is close, the mechanical properties are greatly influenced by the DP and configuration. The DP and the number of chains are the main parameters impacting the compatibility between PE and asphalt, based on the Flory–Huggins parameter analysis. Decreasing the DP of PE (e.g., 50, with a minimum Flory–Huggins parameter and a relative molecular mass of 1300) will significantly increase the compatibility between asphalt and PE. LDPE−2 has better compatibility with asphalt, possibly because LDPE−2 has higher purity. These findings provide valuable insights into plastic thermal cracking and industrial modification practices.
{"title":"Microscopic Properties of Asphalt and Polyethylene at an Extraordinary High Dosage through Molecular Dynamics Simulation","authors":"Yuye Jin, Haoyi Li, Jie Chen, Qianqian Wang, Yanhua Bao, Shuguang Hou","doi":"10.3390/buildings14010164","DOIUrl":"https://doi.org/10.3390/buildings14010164","url":null,"abstract":"Using waste plastics in asphalt mixtures could be an exploratory way to dispose of waste plastics. This study aims to investigate the microscopic properties between asphalt and polyethylene (PE) at an extraordinary dosage of 20 wt.%. Various types of PE with different degrees of polymerization (DP) and structural configurations were considered. Molecular dynamics simulations were used to calculate the mechanical parameters, free volume ratio (FVR), and Flory–Huggins parameter of the resulting PE-modified asphalt (PEA). Two types of PEA were made and characterized by fluorescence microscopy. The simulation results indicate that the addition of PE reduces the density of modified asphalt by less than 5%, and a higher density of PEA is associated with a lower FVR. When the FVR is close, the mechanical properties are greatly influenced by the DP and configuration. The DP and the number of chains are the main parameters impacting the compatibility between PE and asphalt, based on the Flory–Huggins parameter analysis. Decreasing the DP of PE (e.g., 50, with a minimum Flory–Huggins parameter and a relative molecular mass of 1300) will significantly increase the compatibility between asphalt and PE. LDPE−2 has better compatibility with asphalt, possibly because LDPE−2 has higher purity. These findings provide valuable insights into plastic thermal cracking and industrial modification practices.","PeriodicalId":48546,"journal":{"name":"Buildings","volume":"11 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139441704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：