İnşaat Mühendisliği Bölümü Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.11779/1943

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Citation - WoS: 1
Citation - Scopus: 1
A Simplified Approach for Site-Specific Design Spectrum
(2018) Tönük, Gökçe; Kurtuluş, Aslı; Ansal, Atilla
The 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.
An Overview on the Structural Monitoring, Assessment and Retrofitting of Historical Structures With a Focus on 13th Century Monuments
(Springer international Publishing Ag, 2024) Ilki, Alper; Inci, Pinar; Halici, Omer F.; Demir, Cem; Comert, Mustafa; Kuran, Fikret
Monumental historical structures affirm natural and cultural identity and hence they should be transmitted to future generations. The protection and preservation of these structures against aging and natural hazards, particularly seismic actions, requires a comprehensive approach including diagnosis of the present condition of the structure and enhancement of structural capacity for disaster mitigation, if necessary. It is obvious that due to their historical values, any attempt towards the preservation of the monumental historical structures must be carried out with respect to the principles of integrity and authenticity. In this study, the structural performance assessment procedures, implementation of structural health monitoring systems and seismic strengthening strategies are discussed and described with reference to 13th-century monumental historical structures in Turkiye. The structural engineering aspects of recent activities for the restoration and preservation of the Great Mosque and Hospital of Divrigi (a world heritage listed structure) and Sivas Ulu Cami (Mosque) Minaret are briefly presented. In light of the structural analysis and monitoring results, recommendations for interventions to these monumental structures are outlined.
Citation - WoS: 6
Citation - Scopus: 6
Case Study on Seismic Behavior of Aseismically Designed Reinforced Concrete Frame Structures
(2018) Oyguc, Evrim; Oyguc, Resat; Tönük, Gökçe
In this study, the seismic performances of two aseismically designed plan-irregular reinforced concrete frame (RCF) households damaged during the October 23, 2011 Van earthquake are assessed. Since no strong ground motion recordings from the main shock were available, first, strong ground motion parameters of the event are evaluated and then compatible with these parameters suits of real records are selected and scaled to match with the event's simulated acceleration spectrum to be used in the analytical investigations. The results of previous reconnaissance studies, in which one of the present authors was involved, are then discussed. Capacities of the considered RCF's are determined applying a 3D single-run adaptive pushover procedure that is capable of considering the effect of plan irregularities. The performance assessment procedure based on the current 2007 Turkish Earthquake Code is then applied to these investigated buildings. Additionally, nonlinear dynamic time history analyses are carried out using the previously selected time histories. The hysteretic behavior of the considered buildings is examined as the consequence of the conducted analyses and considering the different suits of selected ground motions, the seismic response of the buildings is evaluated in terms of interstorey drifts. None of the buildings are found to satisfy the expected performance level. Moreover, the numerical results are found to have good correlation with the field observation results.
Citation - WoS: 1
Citation - Scopus: 2
Compaction and Shear Strength Behavior of Fresh and Aged Basic Oxygen Furnace (bof) Steel Slag
(2016) Yıldırım, İrem Zeynep; Prezzi, Monica
Use of industrial by-products in geotechnical engineering projects, such as in the construction of highway embankments, is advantageous because large volumes of these materials can be utilized. Basic oxygen furnace (BOF) steel slag is one of these industrial by-products. This paper provides a brief background on the characteristics of BOF steel slag and presents the results of a series of laboratory tests (grain-size analysis, maximum and minimum dry density, compaction, large-scale direct shear tests (LDS) and isotropically consolidated-drained triaxial compression (CID TX) performed on fresh and aged BOF steel slag generated from an Indiana steel plant. BOF steel slag samples from three different batches of production were tested, which allowed an evaluation of both aging processes and the effect of changes in gradation on the mechanical properties. The BOF steel slag tested in this study contained sand-size particles with varying percentages of gravel-and silt-size fractions. The moisture-density relationships for BOF steel slag were irregular with two peaks. Based on the LDS and CID TX test results, the BOF steel slag exhibited superior strength and stiffness characteristics than conventional geo-materials. The mechanical properties of fresh and aged BOF steel slag are discussed in the context of its use in geotechnical applications.
Creating the Flipped Educators of the Future: Leading by Example in the Faculty of Education
(Emerald Group Publishing Ltd., 2016) Kurban, Caroline Fell; Şahin, Muhammed
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Cultural Aspects Inherent in Flipped Learning
(Emerald Group Publishing Ltd., 2016) Kurban, Caroline Fell; Şahin, Muhammed
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Citation - WoS: 36
Citation - Scopus: 47
Cyclic and Monotonic Compression Behavior of Cfrp-Jacketed Damaged Noncircular Concrete Prisms
(2016) İlki, Alper; Dalgıç, Korhan Deniz; İspir, Medine
This 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.
Citation - WoS: 9
Citation - Scopus: 10
Damage Accumulation Modelling of Two Reinforced Concrete Buildings Under Seismic Sequences
(Springer, 2023) Tönük, Gökçe; Oyguç, Reşat; Oyguç, Evrim; Uçak, Doruk
The extent of earthquake damage depends solely on the seismicity, site conditions and vulnerability of the building stock in a region. Hence, studies to assess the seismic behavior of building stocks with similar vulnerabilities are important to mitigate seismic risk in earthquake-prone regions. This study aims to simulate the seismic behavior of selected reinforced concrete (RC) school buildings by modelling damage accumulation under multiple earthquakes sequence. The observed data of two RC school buildings heavily damaged after the 2011 Van earthquake sequence in Turkey, namely, the Gedikbulak and Alakoy schools is used. Among these two school buildings, the Gedikbulak school building collapsed immediately after the main excitation, while the Alakoy school building withstood several seismic sequences, suffering heavy damages. In this study, three-dimensional numerical models that can consider the deterioration effects are developed and the capacities of the buildings were evaluated by conducting a force-based adaptive pushover procedure. Additionally, non-linear dynamic analyses were conducted using the concrete plastic damage model. Both degrading and conventional material models were used to examine the structural response under multiple ground motion sequences. The hysteretic behaviors of the studied buildings are presented. Consequently, analytical results are well correlated with the reconnaissance studies and neither of the considered structures are found to satisfy the design performance level.
Citation - WoS: 9
Citation - Scopus: 10
Determination of Building Age for Istanbul Buildings To Be Used for the Earthquake Damage Analysis According To Structural Codes by Using Aerial and Satellite Images in Gis
(Springer Verlag, 2017) Konukcu, Betül Ergün; Karaman, Himmet; Şahin, Muhammed
Istanbul is located in one of the most active seismic zones in the world. Since Istanbul is the industrial, commercial, cultural and educational center of Turkey, it attracts ongoing migration from all over Turkey. However, those migrations caused unplanned construction and those unplanned constructions led to the formation of vulnerable and undocumented building stock in Istanbul. Many scientific studies estimated that Istanbul is expecting a major earthquake and the expected damage to the structures will be extensive. Therefore, there have been a lot of building damage estimations for the possible Istanbul earthquake to recommended precautions and to be prepared. A major disadvantage of Istanbul case is the lack of knowledge for the absolute number of buildings and the ages of those buildings. Up to now, many studies for Istanbul used the building dataset of Istanbul with the number starting from 1.1 to 1.5 million without the absolute age information. To make a correct or reliable earthquake damage estimation, a building database that contains at least building age, construction type and number of floors is required in most of the earthquake loss assessment software. This paper aims to determine the buildings of Istanbul and the age of them, according to structural codes for the earthquake zones by using aerial and satellite images of Istanbul. The classification should be based on the regulation so as to minimize the age classes and maximize the accuracy. First building regulations in Turkey came into force in 1940 in order to determine essential conditions for the realization of functional, safe and disaster-resistant building design in Turkey. Last updated building code regulations have come into force in 2007 in Turkey. It was also important to investigate the proper building detection method for the aim of this study, and it was determined as the manual digitization. In this study, the buildings of Istanbul and the age of them are determined for every single building, by digitizing the selected aerial and satellite images of Istanbul based on the official structural codes in Turkey. Thus, first the exact number and location of buildings in Istanbul and every single buildings age were determined. The results were also validated with two separate studies of Istanbul for different periods of times. By this way, earthquake damage analysis for the Istanbul buildings can be run for the real building data of Istanbul with any earthquake loss assessment software.
Differentiating Flipped Learning Approaches for the Diverse Needs of the Faculty of Economics, Administrative, and Social Sciences
(Emerald Group Publishing Ltd., 2016) Kurban, Caroline Fell; Şahin, Muhammed
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Disaster Life Cycle in Turkey: Planning, Policy and Regulation Changes Chapter 14
(2016) Ural, Derin Nur
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Citation - WoS: 2
Citation - Scopus: 1
Eaf Ladle Steel Slag as a Geo-Material: Compaction and Shear Strength Characteristics
(2018) Yıldırım, İrem Zeynep; Prezzi, Monica
The 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.
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
...
Engaging Students in a Flipped Language Learning Environment: Stories From the English Language Preparatory Program
(Emerald Group Publishing Ltd., 2016) Kurban, Caroline Fell; Şahin, Muhammed
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Fipped Learning Through the Eyes of the Students: Tales and Anecdotes
(Emerald Group Publishing Ltd., 2016) Kurban, Caroline Fell; Şahin, Muhammed
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Flipped Leadership: Transparency, Vision, Accountability, and Resources
(Emerald Group Publishing Ltd., 2016) Kurban, Caroline Fell; Şahin, Muhammed
As 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.
Flipped Learning Theory, Policies, and Practices
(Emerald Group Publishing Ltd., 2016) Kurban, Caroline Fell; Şahin, Muhammed
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Flipping Language, Literature, and Digital Literacies: Stories From the School of Foreign Languages
(Emerald Group Publishing Ltd., 2016) Kurban, Caroline Fell; Şahin, Muhammed
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From Current Practice To Future Practice: Making the Decision To Flip
(Emerald Group Publishing Ltd., 2016) Kurban, Caroline Fell; Şahin, Muhammed
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Citation - WoS: 4
Citation - Scopus: 4
Gis-Based Assessment of Seismic Vulnerability Information of Old Masonry Buildings Using a Mobile Data Validation System
(American Society of Civil Engineers (ASCE), 2021) Özsoy Özbay, Ayşe Elif; Ünen, Hüseyin Can; Karapınar, Işıl Sanrı
This study proposes a geographic information system (GIS)–based rapid visual screening approach for seismic vulnerability assessment of masonry buildings in culturally and architecturally important historical regions. Through the application of the proposed methodology, a prioritization strategy for seismic vulnerability assessment of the heritage masonry buildings in Galata, a historical center of Istanbul, Turkey, was performed. This approach is based on an integrated methodology including a data collection process conducted through visual inspections and standard survey forms filled on site, generation of a georeferenced building database enabling the calculations and mapping of the vulnerability scores, and camera-based data validation process. The validation process provides an online collaborative mobile mapping system through georeferenced images gathered from the field. By the updatable data validation process, the reliability and efficiency of the GIS-based building database are enhanced by minimizing the errors during the visual screening and the cost of data correction due to reinspection is reduced.

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