İnşaat Mühendisliği Bölümü Koleksiyonu

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

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Citation - WoS: 2
Citation - Scopus: 2
Reconnaissance and Discussion on Ground Motion Induced by the 2023 Türkiye-Syria Earthquake
(Taylor and Francis Ltd., 2025) Towhata, I.; Çağlayan, P.Ö.; Tönük, G.; Erginağ, U.C.; Sendir Torisu, S.
This paper discusses the output from the damage reconnaissance conducted after the 2023 Türkiye-Syria earthquake. First, a large landslide occurred in a limestone gentle slope without much ground water. Second, the ground subsidence in the coastal area does not comply the the local soil conditions and other observed post-seismic situations. Third, the acceleration records exhibit stronger motion with longer period and shorter duration towards the western end of the causative fault and suggest supershear rupture. To understand these features of the ground motion, this paper proposes a hypothetical model that can reproduce these observations to a good extent. © 2025 Taylor & Francis Group, LLC.
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: 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.
Supporting Flipped Learning: Digital Pedagogy, Training, and Resources
(Emerald Group Publishing Ltd., 2016) Kurban, Caroline Fell; Şahin, Muhammed
…
Numerical Seismic Performance Investigation of Aac Infill Walls With Flat-Truss Bed-Joint Reinforcement
(National Technical University of Athens, 2023) İlki, Alper; Halıcı, Ömer Faruk
Autoclaved Aerated Concrete (AAC) is a lightweight, energy-efficient and easy-to-transport material. As a result, AAC walls are becoming increasingly common as an infill solution in earthquake-prone areas such as Turkey, Italy, and Greece. Although infills are considered as secondary components in seismic design, they are extremely vulnerable to damage during earthquakes along both in-plane (IP) and out-of-plane (OOP) directions. Previous post-earthquake site examinations revealed that the failure of infill walls can result in serious injuries and casualties. Furthermore, huge economic losses as well as disruption in the functionality of essential buildings that are supposed to be operational after earthquakes may adversely affect the daily life in the earthquake-affected regions. One of the potential methods for increasing the seismic resilience of infill walls is use of bed-joint reinforcement between infill courses. In this paper, the general approaches in the establishment of the numerical finite element model for infill walls with and without bed-joint reinforcement are presented. The developed model was evaluated according to the previous full-scale experimental test results from strength and damage propagation point of view. The model will be used to investigate the response of infills with various bed-joint reinforcement amounts and height-to-length ratios to generalize the seismic performance improvements obtained by the use of flat-truss reinforcement both in the IP and OOP directions.
Citation - WoS: 10
Citation - Scopus: 15
Out-Of Seismic Performance of Bed-Joint Reinforced Autoclaved Aerated Concrete (aac) Infill Walls Damaged Under Cyclic In-Plane Displacement Reversals
(Elsevier Sci Ltd, 2023) İlki, Alper; Demir, Uğur; Halıcı, Ömer Faruk; Zabbar, Yassin
The infill walls made of Autoclaved Aerated Concrete (AAC), which is a lightweight, fire resistant and energy efficient material, provide effective insulation solutions for building types of structures and becoming more and more popular in earthquake prone regions. Although the number of experimental tests examining the seismic response of clay brick infills is extensive, the amount of prior research on infill walls built of AAC blocks is rather limited. Past research revealed that the use of bed-joint reinforcement is one of the promising solutions to improve the global seismic response of masonry walls by enhancing strength and displacement capacity. In this study, the out-of-plane (OOP) seismic performance of AAC infill walls with flat-truss and innovative cord-type bed-joint reinforcement is experimentally evaluated. Also, consideration is given to the prior in-plane (IP) damage, which was found to degrade the seismic performance of infills in OOP direction. For this purpose, three IP and four OOP, in total, seven experimental tests were performed on four full-scale AAC infill wall specimens. The test parameters were selected in such a way as to make it possible to parametrically compare the OOP performance of AAC infills with flat-truss and cord-type bed-joint reinforcements with unreinforced AAC infill walls, together with the effect of prior IP damage on the OOP response of unreinforced AAC infill walls. It was found that the use of innovative cord-type bed-joint reinforcement improved the OOP strength to a similar extent to what was obtained from the truss-type reinforced specimen. In terms of ultimate displacement and energy dissipation capacity enhancement, the specimen with cord-type reinforcement performed better. In addition, the damages formed due to IP cyclic displacement reversals up to 0.005 drift ratio, which is defined as the drift limit for buildings with brittle infill walls in certain design codes, resulted in a significant reduction in the OOP strength and stiffness properties of AAC infills. The theoretical OOP strength calculations were found to provide unconservative strength values for the IP-damaged specimens.
The Flipped Approach To Higher Education Designing Universities for Today's Knowledge Economies and Societies Preface
(Emerald Group Publishing Ltd, 2016) Sahin, Muhammed; Kurban, Caroline Fell
Citation - WoS: 5
Citation - Scopus: 5
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.
The New University Model : Flipped, Adaptive, Digital and Active Learning (fadal)
(FL Global Publishing, 2019) Şahin, Muhammed; Kurban, Caroline Fell; Mazur, Eric
This book is the academic version of The New University Model with an added focus on Adaptive, Digital and Active Learning (FADAL) and a future perspective on higher education. You can learn about flipping a lesson or class from many educators, but only a few people in the world have experienced flipping multiple university departments or an entire university. What could you learn from spending a few hours with the authors who have deep insight into the process of starting, managing, and scaling Flipped Learning in higher education? MEF University is the first fully flipped university in the world. The 2018 graduating class included students who earned their degrees through Flipped, Adaptive, Digital and Active Learning programs in: mathematics education, guidance and psychological counselling, law, computer engineering, electronics and electrical engineering, industrial engineering, civil engineering, mechanical engineering, economics, business administration, psychology, political science and international relations, architecture, and interior design. In this book, MEF’s rector and the director of the Center for Research and Best Practices in Learning and Teaching share invaluable insights that are not available anywhere else. Whether you are a professor considering flipping your class, a dean or a department head considering expanding your Flipped Learning program, or a rector, president or provost looking for a future perspective on higher education, this book will put you on a clear and proven fast track. The book also includes the framework and set of best practices recently developed by the Academy of Active Learning Arts and Sciences (AALAS) through a cohort of 100 experienced Flipped Learning practitioners in 49 countries. The framework will help you avoid the big mistakes as you embrace and scale Flipped, Adaptive, Digital and Active Learning in higher education. “The book is a must-read for any innovative educator or higher education administrator.” -- Dr. Eric Mazur, School of Engineering and Applied Sciences and School of Education, Harvard University.
Lessons From the Rector of the First Fully Flipped Learning University
(FLR The Flipped Learning 3.0 Magazine, 2018) Şahin, Muhammed
Sahin: MEF Educational Institutions was founded in the 1970s by İbrahim Arıkan, an educator and businessman. In 1996, he founded MEF national and international K-12 schools in Istanbul and Izmir. In 2013, he founded MEF University. As both educator and entrepreneur, Arıkan was in a unique position to establish a university. He was aware the educational system was not well suited to the current needs of students and society and envisioned a totally new educational approach for MEF University. To find this approach, he brought me on board as founding rector. Having been rector of Istanbul Technical University from 2008 to 2012, I had a strong background in innovations in education. During our first meeting, Arıkan made it clear that if he was going to establish a university, it needed to be unique and take a different mentality to the educational needs of today’s students. I vividly remember Ibrahim emphatically declaring that if he could not make a change to higher education, he would call a halt to his aspirations for opening a university.
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.
Citation - WoS: 1
Citation - Scopus: 2
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.
Site Characterization for Site Response Analysis in Performance Based Approach
(Sipringer, 2022) Tönük, Gökçe; Ansal, Atilla
The local seismic hazard analysis would yield probabilistic uniform hazard acceleration response spectrum on the engineering bedrock outcrop. Thus, site-specific response analyses need to produce a probabilistic uniform hazard acceleration response spectrum on the ground surface. A possible performance based approach for this purpose requires a probabilistic estimation of soil stratification and engineering properties of encountered soil layers in the soil profile. The major uncertainties in site-specific response analysis arise from the variabilities of (a) local seismic hazard assessment, (b) selection and scaling of the hazard compatible input earthquake time histories, (c) soil stratification and engineering properties of encountered soil and rock layers, and (d) method of site response analysis. Even though the uncertainties related to first two items have primary importance on the outcome of the site-specific response analyses, the discussion in this article focuses on the observed variability and level of uncertainty in site conditions, related to soil stratification, thickness and type of encountered soil layers and their engineering properties, depth of ground water table and bedrock and properties of the engineering bedrock. Thus, one option may be conducting site response analyses for large number of soil profiles produced by Monte Carlo simulations for the investigated site to assess probabilistic performance based design acceleration spectra and acceleration time histories calculated on the ground surface based on 1D, 2D, or 3D site response analysis with respect to different performance levels.
Citation - Scopus: 23
The Modified Post-Earthquake Damage Assessment Methodology for Tcip (tcip-Dam
(Springer, 2021) Cömert, Mustafa; Ilki, Alper; Halıcı, Ömer Faruk; Demir, Cem
Post-Earthquake damage assessment has always been one of the major challenges that both engineers and authorities face after disastrous earthquakes all around the world. Considering the number of buildings in need of inspection and the insufficient number of qualified inspectors, the availability of a thorough, quantitative and rapidly applicable damage assessment methodology is vitally important after such events. At the beginning of the new millennia, an assessment system satisfying these needs was developed for the Turkish Catastrophe Insurance Pool (TCIP, known as DASK in Turkey) to evaluate the damages in reinforced concrete (RC) and masonry structures. Since its enforcement, this assessment method has been successfully used after several earthquakes that took place in Turkey, such as 2011 Van Earthquake, 2011 Kutahya Earthquake, 2019 Istanbul Earthquake and 2020 Elazig Earthquake to decide the future of damaged structures to be either ‘repaired’ or ‘demolished’.
Seismic Performance of Damaged Code-Conforming Rc Columns Repaired With Sustainable Structural Mortar
(Elsevier B.V., 2024) Kolemenoglu, S.; Halici, O.F.; Demir, C.; Aydemir, C.; Aydemir, M.E.; Ilki, A.
Examining the seismic performance of damaged reinforced concrete (RC) structures after repair applications is vital for an effective post-earthquake disaster management policy. However, the number of experimental studies investigating the seismic behavior of repaired RC members is insufficient, especially for structural members that have endured slight or moderate level damages. In this study, four identical large-scale code-conforming RC columns were tested under combined effects of axial load and reversed cyclic lateral displacements. The reference column was tested until failure, while the remaining three columns were first imposed to lateral displacements until the formation of damages at different levels, then repaired with structural repair mortar that contains recycled raw materials without removing axial load and tested again until failure. The primary objectives of the experimental program are to enhance the knowledge on the post-earthquake performance of damaged RC columns and to investigate the effects of repair applications after slight and moderate damage levels. This paper provides details on the effectiveness of the aforementioned repair technique on the seismic performance of code-complying RC columns damaged at different damage levels. © 2024 Elsevier B.V.. All rights reserved.
Kocaeli 1999 Earthquake, Lessons Learned, Encyclopedia of Earthquake Engineering
(2015) Ural, Derin Nur
...
Citation - WoS: 10
Citation - Scopus: 11
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: 1
Citation - Scopus: 1
Probabilistic Seismic Microzonation for Ground Shaking Intensity, a Case Study in Türkiye
(Springer, 2023) Tönük, Gökçe; Ansal, Atilla
The 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).
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.
Disaster Life Cycle in Turkey: Planning, Policy and Regulation Changes Chapter 14
(2016) Ural, Derin Nur
...

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