İnşaat Mühendisliği Bölümü Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.11779/1943
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Conference Object Impact of Introducing Semi-Rigid Moment Frames on Seismic Response of Braced Frames(2019 ISEC Press, 2019) Shen, Jay; Akbaş, Bülent; Şeker, Onur; Faytarouni, MahmoudMaximum seismic inelastic drift demand in a steel building with braced frames as primary seismic-force-resisting (SFR) system tends to concentrate in few stories without considering inherent participation of designed gravity-force-resisting (GFR) system in actual structural stiffness and strength. The influence of GFR system on stiffness and strength can be taken into account by considering the composite action in beam-to-column shear connections that exist in modern steel building construction to form actual semi-rigid moment-resisting frames. Therefore, modeling semi-rigid moment frames as an equivalent to the GFR system in braced frame buildings could be utilized as a representative to the strength provided by gravity frames. This paper presents a seismic evaluation of a six-story chevron braced frame, with and without semi-rigid moment frame. Four different cases are investigated under a set of ground motions and results are discussed in terms of story drift distribution along the height. The results pointed out that the current findings lay a foundation to conduct further investigation on the seismic performance of braced frames as designed SFR system together with GFR system.Conference Object Citation - WoS: 10Citation - Scopus: 12Implications of Site Specific Response Analysis(Springer, 2018) Tönük, Gökçe; Kurtuluş, Aslı; Ansal, AtillaDefinition of design earthquake characteristics, more specifically uniform hazard acceleration response spectrum, on the ground surface is the primary component for performance based design of structures and assessment of seismic vulnerabilities in urban environments. The adopted approach for this purpose requires a probabilistic local seismic hazard assessment, definition of representative site profiles down to the engineering bedrock, and 1D or 2D quivalent or nonlinear, total or effective stress site response analyses depending on the complexity and importance of the structures to be built. Thus, a site-specific response analysis starts with the probabilistic estimation of regional seismicity and earthquake source characteristics, soil stratification, engineering properties of encountered soil layers in the soil profile. The local seismic hazard analysis would yield probabilistic uniform hazard acceleration response spectrum on the bedrock outcrop. Thus, site specific response analyses also need to produce a probabilistic uniform hazard acceleration response spectrum on the ground surface. A general review will be presented based on the previous studies conducted by the author and his co-workers in comparison to major observations and methodologies to demonstrate the implications of site-specific response analysis.Article Citation - WoS: 16Citation - Scopus: 19Seismic Assessment of Ductile Concentrically Braced Frames With Hss Bracings(Elsevier, 2019) Akbaş, Bülent; Şeker, Onur; Faytarouni, Mahmoud; Shena, JayA study on the seismic ductility demands on square HSS braces in special concentrically braced frames (SCBFs) is presented to address the seismic risk of braces in existing SCBF buildings designed according to both previous and current AISC Seismic Provisions. First, the paper discusses the development of ductility-based fragility curves by employing specimens with various width-to-thickness and slenderness ratios collected from 16 experimental programs from 1978 to today. Second, the constructed fragility curves are used to estimate the vulnerability of square HSS braces to the damage state of fracture using the brace ductility demand as engineering demand parameter. Then, the seismic risk of braces in terms of fatigue life is evaluated under 30 earthquake ground motions using a seven-story office building designed following requirements of previous and current design practice. The study concludes that braces in SCBF designed in compliance with the previous and current AISC Seismic Provisions are subject to a high probability of fracture under earthquake ground motions characterized by different intensity levels, which in turn might lead to underestimation of the overall seismic risk.Book Part Milestones for Success(Emerald Group Publishing Ltd., 2016) Kurban, Caroline Fell; Şahin, Muhammed…Book Part Flipped Leadership: Transparency, Vision, Accountability, and Resources(Emerald Group Publishing Ltd., 2016) Kurban, Caroline Fell; Şahin, MuhammedAs a founding rector of a new institution establishing itself as a fully Flipped university, both the university and I found ourselves in a unique position. Instead of a challenging, change-management process whereby buy in was needed from each stakeholder, all the staff, instructors, and students that started at MEF had come knowing that the education would be Flipped and had agreed to be a part of this approach. From a leadership point of view, this was indeed a privileged position to be in. However, it does not mean that there were not some teething problems along the way. Three main issues arose during the first year including; instructors’ expectations and the clarity of the MEF vision; issues related to the physical infrastructure; as well as questions about assessment.Book Part Cultural Aspects Inherent in Flipped Learning(Emerald Group Publishing Ltd., 2016) Kurban, Caroline Fell; Şahin, Muhammed…Conference Object Citation - WoS: 5Citation - Scopus: 5State of the Art in Application of Seismic Isolation and Energy Dissipation in Turkey(Springer International Publishing Ag, 2023) Şadan, BahadırThis paper summarizes the passive structural control system applications and other related developments in Turkey, emphasizing the period between 2019 and 2022. The country hosts state-of-the-art seismic isolation applications, relatively greater in size, and use more isolators in each project (415 isolators per building on average) compared to the other seismic isolation projects worldwide. Construction of the world's largest seismic isolated building, Istanbul Basaksehir Pine and Sakura City Hospital, covering more than 1 million square meters of area and employing more than 2000 seismic isolators, was completed and has been in service since May 2020. 1915 Canakkale Bridge, constructed in memory of the great war of Canakkale during World War I, is now the world's longest suspension bridge with a 2023m main span length. Eight massive hydraulic dampers were used at the main deck and 48 at the approach viaducts in combination with 72 seismic isolators. Construction of a residential building complex in Istanbul consisting of 16 isolated blocks covering more than 170,000 m(2) area and having 454 seismic isolators is coming to an end very soon. Historical Nusretiye Clock Tower in Istanbul was relocated a few meters over seismic isolators. Historical Goztepe Railway Station in Istanbul was retrofitted to accommodate an additional railway line using seismic isolation technology. Seismic codes for buildings and bridges now include rules for the seismically isolated design of structures. Additionally, all seismic isolation designs must be peer-reviewed by law. A new seismic isolator testing facility was established in Eskisehir to respond to the demand for the large number of isolators that need to be tested.Conference Object Citation - Scopus: 3Wireless Real-Time Monitoring System for Steam Cured Concrete Maturity Calculation(IEEE, 2021) Bekmezci, İlker; Sürücü, Engin; Yıkıcı, AlperInternet of Things (IoT) enabled LoRaWAN® system is adopted to monitor concrete temperatures in real-time via wireless devices embedded within concrete cover. Maturity method is employed to predict compressive strength development of steam cured precast concrete segments produced at an automated manufacturing plant using carousel system. The concrete segments embedded with IoT devices are exposed to steam curing in thermally insulated chambers and transferred to the evacuation line outside of the plant after being demolded. Real-time temperature measurements are continuously compared to predefined target values, so that an email notification could be send to production engineer. In this study, concrete temperatures as well as curing ambient temperatures for two different cases during segment manufacturing are successfully recorded. The details of IoT wireless system to estimate the strength of concrete are presented.Article Citation - WoS: 36Citation - Scopus: 48Cyclic and Monotonic Compression Behavior of Cfrp-Jacketed Damaged Noncircular Concrete Prisms(2016) İlki, Alper; Dalgıç, Korhan Deniz; İspir, MedineThis paper focuses on rehabilitation/strengthening of damaged concrete prisms through external carbon-fiber-reinforced polymer (CFRP) jacketing. In order to evaluate the efficiency of the strengthening method on the damaged concrete prisms, an experimental study including 22 concrete prisms with square and rectangular cross sections was carried out. The parameters of the experimental study are the damage levels. Furthermore, effects of loading scheme (monotonic or cyclic) and cross section type (square and rectangular) were investigated in the existence of damage. The concrete prisms were tested under compression stresses up to three specified axial deformation levels to be representative of slight, moderate, and severe compression damages before strengthening. Tests were repeated after rehabilitation/strengthening of damaged specimens with CFRP jacketing. Test results showed that CFRP rehabilitation/strengthening was effective on enhancement of strength and deformability of the damaged concrete prisms. However, the efficiency of the strengthening method in terms of compressive strength tended to reduce when the level of damage increased. Furthermore, an available model is modified to include the effects of damage level, and the modified model is shown to produce accurate results. (C) 2015 American Society of Civil Engineers.Other Aktif Öğrenme Modelini Kullanan Mef Üniversitesi’nin İddiası: “öğrenmede Sınırsız Özgürlük”(KobiEfor, 2020) Şahin, MuhammedMEF Üniversitesi, yüksek öğretimde dönüşümün anahtarı olarak kabul edilen Flipped Learning modelini ilk uygulayan kurum olarak ilk mezunlarını 2018’de verdi. Aktif öğrenme modelinde yetişen öğrencilerin mezuniyet sonrası işe girme ve öğrenime devam etme oranı yüzde 96’yı buldu. Üniversite bu yıl da finalleri kaldırarak proje haftasını getirdi.Book Part Citation - WoS: 1Organizational Design and Transformation(Emerald Group Publishing Ltd., 2016) Kurban, Caroline Fell; Şahin, Muhammed…Book Part The Flipped Approach To Higher Education : Designing Universities for Today's Knowledge Economies and Societies(Emerald, 2016) Kurban, Caroline Fell; Şahin, Muhammed; Şahin, Muhammedİçindekiler: List of Figures.--List of Tables.--Foreword.--Preface; About the Authors.--Chapter 1 The Socio-Economic and Socio-Technical Nature of Today's World and How This Impacts the Education Sector.--1.1. Employment.--1.2. Education.--1.3. Knowledge, Connectivity, and Cognitive Overload.--1.4. What is Needed from Education Today.--Chapter 2 Flipped Learning: A Transformative Approach Designed to Meet the Needs of Today's Knowledge Economies and Societies.--2.1. What is Flipped Learning?.--2.2. How Did Flipped Learning Develop?.--2.3. How Flipped Learning Meets the Needs of Today's Knowledge Economies and Societies.--Chapter 3 From Current Practice to Future Practice: Making the Decision to Flip.--3.1. Introduction.--3.2. Moving from Current Practice to Future Practice: How the Need for Change Emerged; 3.3. Searching for Future Practice; 3.4. The Big Reveal; Chapter 4 Organizational Design and Transformation; 4.1. Physical and Geographical Infrastructure; 4.2. Human, Social, and Intellectual Capital.--4.3. Technological Infrastructure.--Chapter 5 Flipped Learning Theory, Policies, and Practices.--5.1. Introduction.--5.2. Flipped Learning Theories.--5.3. Flipped Learning Performance Gaps, Causes, and Interventions.--5.4. From Theory to Practice.--5.4.1. A Recommended Course Design Process.--5.4.2. An Instructional Design Handbook.--5.4.3. A Flipped Learning Instructional Design Online Course.--5.4.4. A Flipped Learning Instructional Design Best Practice Checklist.--5.4.5. Support for Students.--5.5. Summary.--Chapter 6 Flipped Leadership: Transparency, Vision, Accountability, and Resources.--6.1. MEF University Rector, Muhammed Şahin. 6.2. Instructors' Expectations6.3. Physical Infrastructure; 6.4. Real-Life Assessment; 6.5. Conclusion; Chapter 7 Supporting Flipped Learning: Digital Pedagogy, Training, and Resources.--7.1. CELT, Caroline Fell Kurban.--7.1.1. Challenges through the Instructors' Eyes.--7.1.2. Challenges through the Students' Eyes.--7.1.3. Challenges through the Institution's Eyes: The Need for an Audit.--7.1.4. Lessons Learnt from the Audit: How the Process Could be Made More Supportive while Still Holding Instructors Accountable.--7.1.5. Lessons Learnt from Implementing Technological Mandates.-- 7.1.6. Where Next? Strategic Plan for the Rest of the Academic Year.--7.2. ITC, Brian Ramey.--7.2.1. The Technological Infrastructure Needed for a Flipped Environment.--7.2.2. Integrating Digital Resources.--7.2.3. Using Data to Effect Change.--7.2.4. The Need for a Secure Video Server.--7.2.5. Conclusion.--7.3. Library Director, Ertuğrul Çiman.--7.3.1. The Architecture of a Library in a Digital World.--7.3.2. The Successes of Using Digital Materials.--7.3.3. The Challenges of Using Digital Materials.--7.3.4. Academic Integrity in a Digital World.Conference Object Seismic Evaluation of Square Hss Braces in Scbf Using Regression Analysis(ISEC Press, 2019) Shen, Jay; Akbaş, Bülent; Şeker, Onur; Faytarouni, MahmoudSince the 1990s, structural engineering practice geared toward the use of hollow structural sections (HSS), notably square HSS, for their economy, and ease of design and construction. According to the AISC Seismic Provisions, during a severe earthquake, these braces could undergo post-buckling axial deformations 10 to 20 times their yielding deformation. However, recent experimental studies indicate that braces made of square HSS, depending on their size, width-to-thickness, and slenderness ratio, are vulnerable to fracture even prior to 10. Therefore, relying on past experimental studies comprised of a few square HSS specimens to develop seismic requirements for SCBF with square HSS could lead to underestimation of the seismic risk. This paper aims to evaluate the fracture risk of braces in existing SCBFs designed in accordance with AISC 341-05 and AISC 341-16 through incremental dynamic analyses (IDA) along with experimentally developed regression model that estimates fracture.Conference Object Citation - WoS: 1Citation - Scopus: 1A Simplified Approach for Site-Specific Design Spectrum(2018) Tönük, Gökçe; Kurtuluş, Aslı; Ansal, AtillaThe design acceleration spectrum requires site investigations and site-response analyses in accordance with the local seismic hazard. The variability in earthquake source and path effects may be considered using a large number of acceleration records compatible with the earthquake hazard. An important step is the selection and scaling of input acceleration records. Likewise, a large number of soil profiles need to be considered to account for the variability of site conditions. One option is to use Monte Carlo simulations with respect to layer thickness and shear wave velocity profiles to account for the variability of the site factors. The local seismic hazard analysis yields a uniform hazard acceleration spectrum on the bedrock outcrop. Site-specific response analyses also need to produce a uniform hazard acceleration spectrum on the ground surface. A simplified approach is proposed to define acceleration design spectrum on the ground surface that may be considered a uniform hazard spectrum.Article Citation - WoS: 1Citation - Scopus: 1Probabilistic Seismic Microzonation for Ground Shaking Intensity, a Case Study in Türkiye(Springer, 2023) Tönük, Gökçe; Ansal, AtillaThe purpose of seismic microzonation is to estimate earthquake characteristics on the ground surface based on a probabilistic approach to mitigate earthquake damage in the foreseeable future for the new buildings, as well as for the existing building stock. The probabilistic analysis and related results are very important from an engineering perspective since the nature of the problem can only be dealt with in a probabilistic manner. The uncertainties associated with these analyses may be large due to the uncertainties in source characteristics, soil profile, soil properties, and building inventory. At this stage, the probability distribution of the related earthquake parameters on the ground surface may be determined based on hazard-compatible input acceleration-time histories, site profiles, and dynamic soil properties. One option, the variability in earthquake source and path effects may be considered using a large number of acceleration records compatible with the site-dependent earthquake hazard. Likewise, large numbers of soil profiles may be used to account for the site-condition variability. The seismic microzonation methodology is proposed based on the probabilistic assessment of these factors involved in site response analysis. The second important issue in seismic microzonation procedure is the selection of microzonation parameters. The purpose being mitigation of structural damage, it is possible to adopt earthquake parameters like cumulative average velocity (CAV) or Housner intensity (HI) that was observed to have better correlation with building damage after earthquakes. A seismic microzonation procedure will be developed with respect to ground shaking intensity considering probabilistic values of the cumulative average velocity (CAV) or Housner intensity (HI).Conference Object Citation - WoS: 2Citation - Scopus: 1Eaf Ladle Steel Slag as a Geo-Material: Compaction and Shear Strength Characteristics(2018) Yıldırım, İrem Zeynep; Prezzi, MonicaThe numerous issues associated with the excess steel slag that is disposed of in landfills every year can be reduced by using it as a geo-material. This paper provides the results of laboratory tests (i.e., sieve, hydrometer, specific gravity, compaction, compaction-particle degradation, and large-scale direct shear with a box size of 30.5 x 30.5 x 20 cm) performed on electric-arc-furnace ladle [EAF(L)] steel slag from a mini-mill in Indiana. Based on standard proctor test results, the maximum dry unit weight values of the EAF(L) steel slag were in the 16.8-to-20 kN/m(3) range at the optimum moisture contents of 11-13%. The results of the large-scale direct shear tests performed on EAF(L) steel slag, compacted at 95-100% relative compaction and sheared with normal stress ranging from 50 to 300 kPa, showed that it has excellent frictional characteristics, with friction angles between 40 and 45 degrees. Based on the results from this study, due to its shear strength characteristics, EAF(L) steel slag has the potential to be utilized as a geo-material to improve the shear strength of various marginal soils.Book Part Disaster Life Cycle in Turkey: Planning, Policy and Regulation Changes Chapter 14(2016) Ural, Derin Nur...Conference Object Citation - WoS: 4Citation - Scopus: 6Near-Fault Earthquake Ground Motion and Seismic Isolation Design(Springer International Publishing Ag, 2023) Harmandar, Ebru; Erdik, Mustafa; Demircioglu-Tumsa, Mine B.; Şadan, Bahadır; Tuzun, Cuneyt; Ulker, OmerSeismic isolation is one of the most reliable passive structural control techniques with adequately established standards for the earthquake protection of structures from earthquakes. However, it has been shown that the seismic isolation systems may not function the best for the near-fault ground motions, since in the proximity of a capable fault, the ground motions are significantly affected by the rupture mechanism and may generate high demands on the isolation system and the structure. In fact, several earthquake resistant design codes state that the seismically isolated structures located at near-fault sites should be designed by considering larger seismic demands than the demand on structures at far-field sites. When the fault ruptures in forward direction to the site most of the seismic energy arrives in coherent long-period ground velocity pulses. The ground-motion prediction equations (GMPEs) typically cannot account for such effects with limited distance metrics and lack adequate data at large magnitudes and near distances. For the reliable earthquake design of the isolated structure in near fault conditions that meets the performance objectives, the 3D design basis ground motion(s) need to be appropriately assessed. Measures in the design of the isolation system, such as modifications in the stiffness and damping characteristics, as well as in the limitation of vertical effects are needed. The behavior of the base-isolated buildings under near-fault (NF) ground motions with fling-step and forward-directivity characteristics are investigated with a rational assessment of design-basis near-fault ground motion, are investigated in a parametric format. The parametric study includes several variables, including the structural system flexibility; number of stories; isolation system characteristic (yield) strength, and the isolation periods related to the post-elastic stiffness. Furthermore, the effect of additional damping by viscous dampers were tested for some selected cases. Important findings observed from the parametric performance results and the overall conclusions of the study are provided.Article Bitişik Yapıların Deprem Performanslarının Ayrı veya Bitişik Olarak Kırılganlık Eğrileri Yardımı ile İncelenmesi(2015) Akbulut, Ali; Boduroğlu, M. HasanMevcut yapıların deprem performans, risk ve güçlendirme analizlerinde, yanındaki yapı ile olan ilişkisini uygun modelleme teknikleri ile analiz aşamasının içine dâhil ederek, sonuçların tekbaşına analiz edilmiş binalara göre olan farklılıklarını incelemek önemli bir konu olarak ortaya çıkmaktadır. Bu çalışmada, literatürdeki komşu binaların birbirleri ile olan etkileşim modelleri, statik itme analizi ve doğrusal olmayan hesap yöntemleri, deprem ivme kayıtlarının bir veri tabanından alınması ve tasarım spektrumuna göre ölçeklenmesi, zaman tanım alanına göre hesap yöntemi, hareket denkleminin Newmark-b yöntemi ile sayısal çözümü ve kırılganlık eğrileri ile bina performans seviyelerinin belirlenmesi konuları incelenmiştir. Bitişik (komşu) ve birbirine benzer binaların, deprem performanslarının birbirileri ile olan etkileşimli ve deprem yönüne göre değişen bir şekilde yapı blokları olarak ele alınıp, hasar görebilirlik-kırılganlık eğrileri yönünden değerlendirilmeleri incelenmiş ve binaların ayrı ayrı analiz edildikleri duruma göre daha farklı sonuçlar verdiği tespit edilmiştir.Conference Object Effects of Curing Temperature on Chloride Migration and Electrical Resistivity of Concrete, Materials, Systems and Structures in Civil Engineering(2016) Çorbacıoğlu, U; Kesler E; Yıkıcı Tahsin Alper; Akkaya Y...
