İnşaat Mühendisliği Bölümü

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A Case Study of Structural Failure of Mounting Systems for Solar Panels from South-Eastern Turkey: An Investigation of Design Parameters under Extreme Weather Events
(2019) Çelik, Gence Genç; Çelik, O.; 101566
One of the biggest demand of growing population, and cornerstone of the socio-economical growth of Nations, Energy is expected today to be Sustainable, Easy to Reach, Economical, and Continuous. As one of the most common and imperative contributors of this Clean Energy Future, Solar Energy in various forms takes a significant role whole around the World. And It shows a great potential particularly for Turkey which imports the majority of its Energy Resources - including Conventional Ones - from Out Sources, to decrease Energy Dependency on Out-of-country Bases and increase awareness to develop competition in New Technology and Production Fields. Based on a Structural Failure Case of Supporting Frames designed for Solar Photovoltaics (PV) in a Solar Power Plant from Turkey, this paper addresses the significance of Local and Site-Specific Investigation of Climate Data to properly decide on Structural Design Parameters -particularly Loads of Snow and Wind- by staying still comformable with National Codes and Standards.
A New Novel Model Proposal For Bond-Slip Behavior Between Angular CFRP Fan Type Anchoraged CFRP Strip and Concrete Surface
(2020) Ghoroubi, Rahim; Mercimek, Ömer; Anıl, Özgür; 306045
In the reinforced concrete, masonry or steel structures should be strengthened or repaired. Carbon fiber reinforced polymers (CFRP) have been widely used for the last 20 years for repairing and strengthening of inadequate earthquake performance of the structures. One of the most important developed design criteria in the retrofit and strengthening details are using CFRP to delay the debonding of the CFRP reinforcement elements. For this reason, the uses of anchors in the reinforcement details developed by using CFRP and also researches on this subject have increased substantially. In the literature, research on bond-slip models developed for fan type CFRP anchors and anchored CFRP strips used in reinforcement details are limited in comparison to non-anchored strips. However, in studies on this subject, anchors are placed at 90o to the axial tensile force applied to the CFRP strips. Axial force-bearing strength and bond-slip models of CFRP strips with the different anchored angle under axial tensile strengths have not been found in the literature. For this reason, an experimental study was carried out and 28 specimens of angled anchored CFRP strip test specimen, which was bonded to the concrete surface, was tested under the influence of axial tensile force with an experimental setup designed by the authors. The variables studied in the experimental study are the CFRP strip width and the fan type CFRP anchor angle placed on the CFRP strip. As a result of the experimental study, an equation was proposed for calculating the bearing strength values of angled anchored CFRP strips and a new proposal for the bond-slip model was developed.
A Predictive Ground-Motion Model for Turkey and Its Comparison with Recent Local and Global GMPEs
(2011) Cağnan, Zehra; Akkar, Sinan; Gülkan, Polat; 5743
We present a local ground motion prediction equation (GMPE ) for estimating the peak ground-motion values that was derived using the recently compiled Turkish strong motion database . The new GMPE is comparable with the recent global GMPEs in terms of model sophistication and quality of underlying database. Using this equation, we explore the inter-event , inter-station ground motion variability of the recent Turkish strong motion database as well as suitability of some local and global GMPEs for regional seismic hazard assessment analyses. The inter-event error underlines the distinguishing characteristics of few earthquakes, suggesting that the use of local GMPEs can be important especially when specific scenario studies are to be carried out. The inter-station variability allowed us to detect stations with outlier site response and to investigate the goodness of the employed site effect s model. Results also indicate suitability of some global and local GMPEs for use in regional seismic hazard assessments together with the model presented in this study. These should be combined through a logic tree scheme to reduce both aleatory and epistemic uncertainty in local hazard assessments.
Açılı Cfrp Ankrajlı Şeritler ile Beton Yüzey Arasındaki Gerilme Deformasyon Davranışı için Yeni Bir Model Önerisi
(2020) Özgür, A. C. Anıl; Ghoroubi, Rahim; Mercimek, Ömer
Betonarme, çelik veya yığma yapılar birçok farklı nedenden dolayı güçlendirilmeleri veya onarılmaları gerekmektedir. Karbon takviyeli elyaf kumaşlar (CFRP) deprem performansı yetersiz yapıların onarım ve güçlendirme çalışmalarında son 20 yıldır yaygın olarak kullanılmaktadır. CFRP ile geliştirilen onarım ve güçlendirme detaylarında önemli olan tasarım kriterlerinden biri CFRP elemanların yüzeyden soyulmalarını geciktirmektir. Bu amaçla CFRP ile geliştirilen güçlendirme detaylarında ankrajların kullanılması artış göstermiştir. Güçlendirme detaylarında kullanılan fan tipi CFRP ankrajlı CFRP şeritler ile ilgili gerilme-kayma deplasmanı modellerinin ankrajsız CFRP şeritlere göre çok daha sınırlı sayıda olduğu görülmektedir. Bu konudaki sınırlı sayıdaki çalışmada ankrajlar CFRP şeritlere uygulanan eksenel çekme kuvvetine göre 90o açılı olacak şekilde yerleştirilmiştir. Yapılan literatür taramasında eksenel yüke göre değişik açılarda yerleştirilen ankrajlı CFRP şeritlerin eksenel kuvvet taşıma gücü ve gerilme kayma deplasmanı modelleri ile ilgili bir çalışmaya rastlanmamıştır. Bu nedenle deneysel bir çalışma düzenlenmiş ve 28 adet beton yüzeyine yapıştırılan açılı ankrajlı CFRP şerit deney elemanı eksenel çekme kuvveti etkisinde yazarlar tarafından tasarlanan bir deney düzeneği kullanılarak test edilmiştir. Deneysel çalışmada incelenen değişkenler CFRP şerit genişliği ve CFRP şeritler üzerindeki CFRP fan tipi ankrajların açılarıdır. Deneysel çalışma sonucunda açılı ankrajlı CFRP şeritlerin maksimum taşıma gücü değerlerinin hesaplanması için bir denklem ve yeni bir gerilme kayma deplasmanı modeli önerilmiştir.
Adaptation of generalized Hill inequalities to anisotropic elastic symmetries
(2011) Dinçkal, Çiğdem; 26773
Mechanical and elastic behaviors of anisotropic materials are investigated in an innovative way. This is based on generalized Hill inequalities. From different type of anisotropic elastic symmetries, numerical examples are given. Constructing bounds on effective eigenvalues provides a deeper understanding about mechanical behavior of anisotropic materials. Generalized Hill inequalities are adapted to all anisotropic elastic symmetries. The materials selected from the same symmetry type which have larger interval between the bounds, are more anisotropic whereas smaller interval between the bounds, are closer to isotropy. Besides it is proved that there are relations between bulk and shear modulus and eigenvalues of cubic and isotropic symmetry and by these relations, two linear invariants are found out.
Ahşap Bağlantı Noktalarında Mekanik Ankraj Sayısı ve Yerleşim Şeklinin Kayma Gerilmesi-kayma Deplasmanı Davranışı Üzerindeki Etkilerinin Deneysel Olarak İncelenmesi
(2021) Acehan, Ayşegül Özden; Mercimek, Ömer; Ghoroubi, Rahim; Anıl, Özgür
Ahşap yapılar ve yapı elemanlarında yapıştırıcı ve mekanik bağlantı elemanları ile bir araya getirilmiş birleşim bölgerinin genel yük-deplasman davranışı, kayma gerilmesi- kayma deplasmanı davranışları, yapısal sistemin kapasitesi ve göçme mekanizmaları üzerinde son derece etkilidir. Ahşap-ahşap bağlantı bölgelerinin davranışları, malzemenin mekanik özelliklerine, yapısına ve türüne göre çok büyük oranda değişim gösteren farklı kayma gerilmesi-kayma deplasmanı davranışları sergileyen, incelenmesi gerekli olan önemli bir konudur. Ahşap yapı elemanlarının yapıştırıcı ve yapıştırıcı ile birlikte mekanik ankrajlar ile birleştirilmesi durumunda genel yük-deplasman davranışlarının, bağlantı bölgesindeki gerilme dağılımları ile kayma gerilmesi - kayma deplasmanı davranışlarının incelendiği kapsamlı bir deneysel çalışmaya literatürde rastlanmamıştır. Bu nedenle deneysel bir çalışma planlanmıştır. Bu çalışma kapsamında birbirlerine yapıştırıcı ve yapıştırıcı ile birlikte mekanik ankrajlar ile bağlanmış olan, kenetlenme uzunlukları 180, 240 ve 350 mm olarak değişim gösteren ahşap bağlantı bölgelerinin, eksenel çekme yükü etkisi altındaki genel yük deplasman davranışları deneysel olarak incelenmiştir. Ayrıca çalışma kapsamında birleşim bölgesinde kullanılan mekanik ankraj sayısı ve yerleşiminin değişim göstermesinin, genel yük-deplasman davranışı ve kayma gerilmesi-kayma deplasmanı davranışları üzerindeki etkileri de araştırılmıştır.
An investigation of the hydrodynamic and fish behavior characteristics of the brush-type fish passage: Iyidere (Turkey) field study
(2017) Küçükali, Serhat; 20413
Analysis of Elastic Anisotropy of Wood Material for Engineering Applications
(2011) Dinçkal, Çiğdem; 26773
This paper presents a convenient method to describe the degree of the elastic anisotropy in a given type of wood and then discusses its practical values. Besides mechanical and elastic behaviour of wood are investigated in order to understand the optimum mechanical behaviour of it in selected directions. Bounds on the wood elastic constants have been constructed in terms of elasticity and compliance tensors for any type of woods by developing Hill (1952) approach. So for any type of wood with known elastic constants, it is possible to choose the best set of elastic constants (effective elastic constants) which determine the optimum mechanical and elastic properties of it. Bounds on the wood elastic constants as well as the degree of elastic anisotropy are significant and critical cases in design of any engineering and structural materials made up of wood.
Citation - WoS: 7
Citation - Scopus: 17
An Analysis on the Relationship Between Safety Awareness and Safety Behaviors of Healthcare Professionals, Ankara/Turkey
(Oxford Univ Press, 2020) Uzuntarla, Fatma; Kucukali, Serhat; Uzuntarla, Yasin; 20413
Objectives: This descriptive study aims to examine the relationship between the safety awareness of healthcare professional and their safety behaviors. Methods: The study was carried out on 418 healthcare professionals working in a training and research hospital in Ankara/Turkey. The survey method was used as data collection tool. The questionnaire consisted of 3 sections and 18 questions. First section consisted of questions on sociodemographic characteristics and, second section consisted of the awareness scale and third section consisted of safety behaviors scale. Results: The safety awareness and safety behaviors are scored on a scale from 1 (completely disagree) to 5 (completely agree). The safety awareness and safety behaviors has an average score of 3.85 +/- 0.81 and 3.56 +/- 0.82, respectively. The safety awareness and safety behavior levels of healthcare professionals were found to be high. Conclusion: A significant positive correlation was found between safety awareness and safety behaviors and it was concluded that the increase in safety awareness led to an increase in safety behavior.
Citation - WoS: 3
Citation - Scopus: 4
An Analytical Investigation of Rigid Plastic Beams Under Impact Loading
(Gazi Univ, Fac Engineering Architecture, 2015) Gultop, Tekin; Gültop, Tekin; Yilmaz, Mahmut Cem; Alyavuz, Bahadir; 5168; İnşaat Mühendisliği
Beams might be subjected to impact loading which is a particular type of dynamic loading during their service lives. In this study the behaviour of beams under low speed impact loading has been investigated analytically. Simply supported and fixed ended beams have been analyzed with the assumption of rigid plastic behaviour. The collapse mechanism has been assumed to emerge by the instant formation of plastic hinges, hence, a limit analysis has been performed under dynamic loading considering the conservation principles of energy and momentum. The behaviour of rigid plastic beams under impact loading has been compared to the behaviour of elastic beams under similar loading conditions.
Citation - WoS: 11
Citation - Scopus: 15
Assessment of the Effectiveness and the Initial Cost Efficiency of Hot Recycled Asphalt Using Polymer Modified Bitumen
(Elsevier, 2023) Almusawi, Ali; Shoman, Sarmad; Lupanov, Andrei P.
The drastic increase in environmental concerns and increasing costs of road construction materials necessitate evaluating some alternative solutions. One of the most suitable alternatives is recycling old asphalt pavement to produce reclaimed asphalt pavement (RAP). The RAP materials have been commonly combined with asphalt mixtures during pavement construction. Incorporating RAP material should demonstrate an equivalent or better performance than conventional asphalt mixtures. Conversely, the inclusion of RAP mainly needs to improve performance compared to conventional asphalt mixtures. The key issue of using RAP is to restore the loss properties of aged materials and normally asphalt Agent Rejuvenator (ARA) was used. Also, adding polymers with RAP into the asphalt mixture becomes necessary to obtain the required performance. This study investigated the RAP effects of elastomeric polymer on the performance of the asphalt mixture following Russian standards (GOST). The impact of using PMB with RAP material on the asphalt mixture's performance was primarily considered by employing tests that can reveal the adhesion property. Additionally, the performance of the pavement was evaluated in terms of strength and low-temperature cracking. For this purpose, numerous test methods were implemented to appraise the asphalt performance, such as compressive strength, moisture susceptibility, shear resistance, tensile strength, porosity of the mineral particles, and residual porosity. The results indicated that the overall performance of the asphalt mixtures prepared with RAP and combined with polymer depicted a better performance. Moreover, the initial construction cost for each asphalt composition was estimated and compared. The utilization of PMB increased the cost of the asphalt mixture. However, such an increase in the cost would lead to an increase in the overall performance, especially for RAP mixtures.
Citation - WoS: 81
Citation - Scopus: 106
Availibility of Renewable Energy Sources in Turkey: Current Situation, Potential, Government Policies and the Eu Perspective
(Elsevier Sci Ltd, 2012) Kucukali, Serhat; Baris, Kemal; 20413
This study aims to explore the availability and potential of renewable energy sources in Turkey as well as assessing related government policies, financial and environmental aspects of renewable energy projects. Turkey is a country which has the highest hydropower, wind and geothermal energy potential among European countries. As a European Union (EU) candidate several incentives were developed in Turkey for electricity generation from renewable energy sources by the enactment of Law No. 5346 in 2005 which was later restructured by Law No. 6094 in 2010. The most important ones are: ease of land acquisition and feed-in-tariffs which promise purchasing of electricity generated and domestic manufacturing of equipment by the private companies with a price of 5.30-9.69 and 0.3-2.55 (sic)c/kWh, respectively, depending on the type of the renewable and the equipment. However, feed-in tariff amounts take reservoir area into account instead of installed capacity for hydroelectric power plants. Moreover, Environmental Impact Assessment (EIA) report is not mandatory for all renewable energy plants. According to the multi-criteria analysis tool developed in this study to evaluate the renewable energy source (RES) technologies the most appropriate renewable energy alternative for Turkey is biomass, simply because of the highest social benefit among others. (C) 2011 Elsevier Ltd. All rights reserved.
Citation - WoS: 21
Citation - Scopus: 24
Behavior of Glulam Timber Beam Strengthened With Carbon Fiber Reinforced Polymer Strip for Flexural Loading
(Sage Publications Ltd, 2021) Isleyen, ummu K.; Ghoroubi, Rahim; Mercimek, Omer; Anil, Ozgur; Erdem, Recep Tugrul
In the last 20 years, the use of wooden structures and their dimensions have gradually increased. The wood application has increased in different structures such as multistory buildings, sports, industrial facilities, road and railway bridges, power transmission lines, and towers. The widespread use and size of wood structures have increased the research on developing special types of wood products supported by composite materials. Laminated wood elements are the leading composite wood materials. Laminated wooden beams allow making much larger openings than standard solid wood structural elements. The development of the sizes and usage areas of wooden structures has increased the capacity of glulam structural elements and reveals the need to improve their performance. Carbon fiber reinforced polymers (CFRPs) are the most suitable options for increasing the bearing capacity values of glulam beams and improving general load-displacement behaviors. In this study, the use of CFRP strips in different layouts to increase glulam wooden beams and the application of CFRP fan-type anchors in the CFRP strip endpoints are the studied variables. Anchored and non-anchored glulam wooden beams reinforced with CFRP strips with different layouts were tested using a three-point bending test. The ultimate load capacity, initial stiffness, displacement ductility ratio, energy dissipation capacity, failure mechanisms, and general load-displacement behavior of wooden beam test specimens were obtained and interpreted as a result of the experiments.
Citation - WoS: 4
Citation - Scopus: 4
Behaviour of Steel Beams Retrofitted With Anchored Carbon-Fibre Polymer Strips
(Ice Publishing, 2022) Mercimek, Omer; Ghoroubi, Rahim; Baran, Mehmet; Anil, Ozgur
Steel bridge beams can be damaged due to increased traffic loads and environmental impacts. An experimental study on the use of bonded and mechanically anchored carbon-fibre-reinforced polymer (CFRP) strips was undertaken to assess the retrofitting of such steel beams. The number of mechanical anchors used in the ends of the bonded strips was varied from zero to eight. The steel beam samples were tested under four-point loading. Loading was applied as an increasingly high static load and a low repetitive fatigue load. The load-displacement behaviour under the effects of static and fatigue loading and the strain distributions along the strips were measured and interpreted. The results showed that retrofitting cracked steel beams with CFRP strips is an effective method. In addition, retrofitting with anchored strips increased the performance of cracked beams under the effects of both static and fatigue loading.
Biogas Energy in Turkey: Current Situation, Sustainability and Policy Implications, Energy Science and Technology
(2014) Bölük, G.; Küçükali, Serhat; 20413
Birden Fazla Boşluklu Çift Doğrultulu Betonarme Döşemelerin Zımbalama Performansının İyileştirilmesi için Tekstil ile Güçlendirilmiş Sıva Şeritler ile Güçlendirilmesi
(2021) Mercimek, Ömer; Ghoroubi, Rahim; Anıl, Özgür; Baran, Mehmet
Betonarme kirişsiz döşemelerde meydana gelebilecek olan ani ve gevrek bir şekilde, hiçbir deformasyon belirtisi göstermeden oluşan zımbalama göçme mekanizması yapı içerisinde yaşayanlara zarar verebilecek son derece tehlikeli bir göçme şeklidir. Bu nedenle tasarım aşamasında kaçınılan göçme mekanizmalarının başında gelmektedir. Betonarme döşemelerde havalandırma, elektrik veya dogalgaz gibi alt yapı sistemlerinin geçirilmesi veya merdiven ya da asansör boşluğu gibi mimari zorunluluklar nedeniyle bırakılan boşlukların, döşemelerin zımbalama dayanımını ve davranışını olumsuz etkilediği bilinmektedir. Ancak birden fazla boşluklu çift doğrultulu betonarme döşemelerin zımbalama yüklemesi etkisi altındaki davranışının incelendiği bir araştırmaya literatürde rastlanmamıştır. Bu nedenle betonarme çift doğrultulu döşemelerde birden fazla boşluğun döşemelerin zımbalama davranışı üzerindeki olumsuz etkilerinin belirlenmesi ve boşlukların meydana getirdiği davranış problemlerinin azaltılabilmesi için tekstil ile takviye edilmiş sıva şeritler ile döşemelerin güçlendirilmesinin incelendiği deneysel bir çalışma planlanmıştır. Bu çalışma kapsamında biri boşluksuz referans elemanı, 4 deney elemanı ise 300x300 mm boyutlarında kare kesitli iki adet boşluklu olacak şekilde toplamda 5 döşeme deney elemanı üretilmiştir. Boşluklu deney elemanlarının ikisi tekstil ile güçlendirilmiş sıva katmanlı (TGSK) şeritler ile güçlendirilerek deney elemanlarının zımbalama davranışı üzerinde boşlukların meydana getirdiği olumsuz etkilerin ne ölçüde iyileştirilebildiği deneysel olarak araştırılmıştır. Çalışma kapsamında TGSK şeritler ile geliştirilen ve uygulanan güçlendirme metodunun döşemelerin zımbalama dayanımını önemli ölçüde artırdığı, boşlukların meydana getirdiği olumsuz etkileri sınırlandırdığı görülmüştür.
Brush-baffle fish pass: a continuous migration corridor for fish
(2016) Küçükali, Serhat; 20413
Buildings Subjected to Recurring Earthquakes: A Tale of Three Cities
(2011) Bayhan, Beyhan; Polat, Gülkan; 5743
Three different buildings built according to the same design have experienced three different near-field strong ground motions over a period of 11 years in three different cities in Turkey. The input motion was known for each because strong-motion sensors were located adjacent or close to the buildings. We examine the performance of the five-story, reinforced concrete-frame buildings. Bidirectional nonlinear time history and nonlinear static analyses on 3-D analytical models are performed. The principal focus is to assess whether the analytical model of the buildings could indicate column-beam damage consistent with that observed at the sites after the earthquakes. Results illustrate that nonlinear time history analyses are capable of indicating the occurrence of shear failure in captive columns; however, they overestimate the global damage. The overestimation is greater where the building sustained a pulse-type motion without significant distress. It appears that difference between visual observations and analytical results persists.
Closure to "local Scour at Triangular Labyrinth Side Weirs Located on an Alluvial Channel" by Mustafa Tunc, Muhammet Emin Emiroglu, and Mustafa Gogus
(2023) Tunç, Mustafa; Emiroğlu, Muhammet Emin; Göğüş, Mustafa; 6062
Citation - WoS: 6
Citation - Scopus: 7
Crack Width - Seismic Intensity Relationships for Concrete Gravity Dams
(Taylor & Francis Ltd, 2024) Soysal, Berat Feyza; Arici, Yalin; 157572
Seismic assessment of plain concrete structures like gravity dams is generally conducted based on cracking. The responses of two types of gravity dams, i.e. the conventional and roller compacted concrete (RCC), were investigated in this study using a discrete element tool coupled with special reservoir elements. Using incremental dynamic analysis, the relationship between the seismic intensity measures and crack widths on the U/S face of the monolith was obtained. The damage accumulation on conventional and RCC dams was different: The cumulative cracking on the upstream face of the monolith correlated well to a seismic intensity measure representing base shear.

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