Civil Engineering

Permanent URI for this collectionhttps://hdl.handle.net/10679/312

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    ArticlePublicationOpen Access
    Fly-ash evaluation as potential EOL material replacement of cement in pastes: Morpho-structural and physico-chemical properties assessment
    (MDPI, 2022-04-24) Vasile, B. S.; Nicoara, A. I.; Surdu, V. A.; Ene, V. L.; Neacsu, I. A.; Stoica, A. E.; Oprea, O.; Boierasu, I.; Trusca, R.; Vrabec, M.; Miklavic, B.; Sturm, S.; Ow-Yang, C.; Gulgun, M. A.; Bundur, Zeynep Başaran; Civil Engineering; BUNDUR, Zeynep Başaran
    The main objective of the study was to produce alternative binder materials, obtained with low cost, low energy consumption, and low CO2 production, by regenerating end-of-life (EOL) materials from mineral deposits, to replace ordinary Portland cement (OPC). The materials analyzed were ash and slag from the Turceni thermal power plant deposit, Romania. These were initially examined for morphology, mineralogical composition, elemental composition, degree of crystallinity, and heating behavior, to determine their ability to be used as a potential source of supplementary cementitious materials (SCM) and to establish the activation and transformation temperature in the SCM. The in-situ pozzolanic behavior of commercial cement, as well as cement mixtures with different percentages of ash addition, were further observed. The mechanical resistance, water absorption, sorptivity capacity, resistance to alkali reactions (ASR), corrosion resistance, and resistance to reaction with sulfates were evaluated in this study using low-vacuum scanning electron microscopy.
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    ArticlePublicationOpen Access
    Rateworkspace: BIM integrated post-occupancy evaluation system for office buildings
    (International Council for Research and Innovation in Building and Construction, 2022-04) Artan, D.; Ergen, E.; Kula, B.; Işın, Gürşans Güven; Civil Engineering; IŞIN, Gürşans Güven
    The feedback obtained from occupants regarding their comfort needs and performance of buildings is critical for assessing occupant satisfaction, identifying the operation and maintenance (O&M) issues in time and for improving resource efficiency in buildings. Current facility management (FM) systems and occupant feedback collection practices, however, have limitations in supporting effective decision-making in FM, as they lack the necessary contextual data related to the occupant feedback (e.g., building geometry, systems, elements). Building Information Modeling (BIM)-enabled FM systems are used for combining different types of FM information with building models; however, occupant feedback is still not effectively utilized in FM since it is not integrated with BIM. In this study, a BIM integrated post-occupancy evaluation system prototype is developed for: (1) collecting occupant feedback along with the contextual information related to the feedback items in a structured way, and (2) presenting this information as integrated with BIM to the facility managers. This enables conducting spatio-temporal queries and supports effective decision-making by visualizing the collected feedback. The prototype was designed by using qualitative shadowing with FM teams to identify information needs and use case analysis to determine how contextual data integrated with BIM could be collected from office occupants who are non-technical persons with limited information on building models. This paper identifies the FM query categories that are required to process the occupant feedback and describes the RateWorkSpace prototype developed for office buildings. The deployment of the prototype in a real-world office demonstrates that the proposed system is applicable, practical, usable, and that real-time building performance data can be both collected and analysed with the developed system. This has the potential to increase the effectiveness of the FM and O&M processes, and help to create office spaces with optimized energy use and occupant comfort that also supports occupant well-being and productivity.
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    ArticlePublicationOpen Access
    Risky maritime encounter patterns via clustering
    (MDPI, 2023-04-28) Oruç, Muhammet Furkan; Altan, Yiğit Can; Civil Engineering; ALTAN, Yiğit Can; Oruç, Muhammet Furkan
    The volume of maritime traffic is increasing with the growing global trade demand. The effect of volume growth is especially observed in narrow and congested waterways as an increase in the ship-ship encounters, which can have severe consequences such as collision. This study aims to analyze and validate the patterns of risky encounters and provide a framework for the visualization of model variables to explore patterns. Ship–ship interaction database is developed from the AIS messages, and interactions are analyzed via unsupervised learning algorithms to determine risky encounters using ship domain violation. K-means clustering-based novel methodology is developed to explore patterns among encounters. The methodology is applied to a long-term dataset from the Strait of Istanbul. Findings of the study support that ship length and ship speed can be used as indicators to understand the patterns in risky encounters. Furthermore, results show that site-specific risk thresholds for ship–ship encounters can be determined with additional expert judgment. The mid-clusters indicate that the ship domain violation is a grey zone, which should be treated carefully rather than a bold line. The developed approach can be integrated to narrow and congested waterways as an additional safety measure for maritime authorities to use as a decision support tool.