Browsing by Author "Güneş, Burcu"

Now showing 1 - 6 of 6

Citation Count: 3
Approximate seismic evaluation methods for large building inventories with high variability in their seismic resistance
(2006) Gunes,B.; Yakut,A.; Gunes,O.; Department of Civil Engineering
Seismic hazard mitigation for urban infrastructures located in seismic regions is a challenge faced by many countries around the world, especially those with infrastructures known for their variability in quality of construction and compliance with the seismic codes. Two recent major earthquakes that hit the densely populated urban areas in Northwest Turkey resulted in a large-scale destruction and loss of life. Scientific studies indicate that the probability of occurrence of another severe earthquake along the North Anatolian Fault near Istanbul is quite high in the next few decades. This situation presents a serious threat to the large building stock and their occupants in Istanbul and adjacent areas. Structures in these areas are known to have high variability in their seismic resistance, which makes it difficult to estimate the potential losses in case of a major earthquake. Thus, there is an urgent need for a systematic strategy that will allow for rapid and reliable assessment of the seismic risk associated with existing buildings through an effective methodology that properly considers the local infrastructure characteristics. In this paper, approximate methods for seismic assessment of buildings are reviewed and are evaluated through their application to a group of 131 reinforced concrete frame buildings located in various seismic regions of Turkey. The results show that the recently developed preliminary methods that are customized for the local building characteristics provide improved prediction of seismic hazard, and may serve as an efficient and reliable risk assessment tool upon further improvement and calibration. The first stage procedures show large variability and result in considerable cases of misclassifications.
Citation Count: 18
Damage in Reinforced-Concrete Buildings during the 2011 Van, Turkey, Earthquakes
(Asce-amer Soc Civil Engineers, 2014) Baran, Eray; Mertol, Halit Cenan; Gunes, Burcu; Civil Engineering; Department of Civil Engineering
Two major earthquakes with magnitudes Mw=7.2 (ML=6.7) and ML=5.6 occurred in eastern Turkey on October 23 and November 19, 2011. The maximum measured peak ground accelerations for the two ground motions were 0.18g and 0.25g, respectively. The earthquakes resulted in various levels of damage to RC moment-resisting frame buildings ranging from minor cracking in brick partition walls to total collapse. This paper summarizes the field observations of the Atilim University Reconnaissance Team carried out in the region a few days after the two main shocks with an emphasis on the performance of RC buildings. A summary of the evolution of the Turkish seismic design code during the last 35 years is given, followed by an explanation of the behavior of RC buildings during the October 23 and November 9 earthquakes. The deformation types that were commonly observed in the heavily damaged or collapsed RC buildings include plastic hinging in columns attributable to stiffer beams, localization of damage in ground-story columns attributable to changes in the stiffness of the lateral load-resisting system caused by brick partition walls, and shear failure of columns caused by discontinuities in the partition walls adjacent to the columns. Poor concrete quality, inadequate development and lap splice length for reinforcement, and inadequate confinement in columns also contributed to the poor seismic behavior.
Citation Count: 3
Design of FRP retrofitted flexural members against debonding failures
(2006) Gunes,O.; Karaca,E.; Gunes,B.; Department of Civil Engineering
Use of fiber reinforced polymer (FRP) composites in seismic retrofitting of structural members has been steadily increasing in recent years. An important design issue with significant performance and safety implications is the debonding of externally bonded FRP reinforcement in flexural members. This paper provides the highlights of an experimental and analytical research aimed at understanding and modeling of debonding failures in FRP strengthened reinforced concrete beams. An evolutionary experimental program investigated debonding failure mechanisms and modes in beams strengthened in shear and/or flexure in various configurations and tested under monotonic and cyclic loading. A newly developed fracture mechanics based model considers the global energy balance of the system and predicts the debonding failure load by characterizing the dominant mechanisms of energy dissipation during debonding. Validation of the model is performed using experimental data obtained from several independent experimental studies.
Citation Count: 11
Use of UHPC in Bridge Structures: Material Modeling and Design
(Hindawi Ltd, 2012) Gunes, Oguz; Yesilmen, Seda; Gunes, Burcu; Ulm, Franz-Joseph; Department of Civil Engineering
Ultra-high-performance concrete (UHPC) is a promising new class of concrete material that is likely to make a significant contribution to addressing the challenges associated with the load capacity, durability, sustainability, economy, and environmental impact of concrete bridge infrastructures. This paper focuses on the material modeling of UHPC and design of bridge girders made of UHPC. A two-phase model used for modeling the behavior of UHPC was briefly discussed, and the model was implemented in a preliminary design case study. Based on the implemented design and the reported use of UHPC in bridge applications, the advantages, limitations, and future prospects of UHPC bridges were discussed, highlighting the need for innovative research and design to make optimum use of the favorable properties of the material in bridge structures.
Veri kullanımlı deprem hasar tespit yöntemi
(2005) Mohamed, Ahmed S.; Güneş, Burcu; Department of Civil Engineering
V ÖZET BİR LINUX PC KÜMESİ ÜZERİNDE PVM VE MPI PARALEL BİLGİİŞLEM İLETİŞİM ARAYÜZLERİNİN PERFORMANSLARININ İNCELENMESİ BAŞGÖK, Burak Yüksek Lisans Bitirme Projesi, Uluslararası Bilgisayar Enstitüsü, Bitirme Proje Yöneticisi: Doç. Dr. Mehmet Emin DALKILIÇ Eylül 2003, 30 sayfa Bu projede, gerekli donanım ve yazılım bileşenleri kullanılarak bir Linux PC kümesi oluşturulmuş ve bu küme üzerinde PVM ve MPI paralel iletişim arayüzlerinin performans incelemesi, bilgisayarda üç boyutlu foto-gerçekçi görüntüler oluşturmak amacıyla kullanılan POVRAY yazılımı ve yanısıra hem PVM hem de MPI arayüzleri ile uyumlu şekilde paralel olarak çalışabilen iki farklı POVRAY uyarlaması olan PVMPOV ve MPI-Povray kullanılarak gerçekleştirilmiştir. Ayrıca HPL (High Performance Linpack) denektaşı testi kullanılarak Linux kümesinin 'Gflops' cinsinden performansı tespit edilmiştir. Anahtar Kelimeler: Küme bilgi-işlem, Linux PC kümeleri, PVM, MPI, POVRAY, PVMPOV, MPI-Povray, HPL, Linpack
Yumuşak kat düzensizliğine sahip binaların analizi
(2007) Altuntop, Mehmet Alper; Güneş, Burcu; Akış, Tolga; Department of Civil Engineering
Ülkemizde ve dünyada oluşan depremlerde görüldüğü üzere yumuşak kat düzensizliği, yapıların güvenilirliği ve stabilitesi açısından oldukça ciddi bir tehdit oluşturmaktadır. Yumuşak kat düzensizliğine sahip sayısız binanın bu depremlerde ağır hasar alması veya yıkılması, bu tip yapıların sismik hareketler altındaki davranış ve kapasitelerinin belirlenmesine yönelik doğrusal veya doğrusal olmayan analiz metodlarının araştırılmasına yol açmıştır. Bu tezin amacı, yumuşak katlı binaların doğrusal olmayan davranışlarını artımsal itme ve zaman tanım alanında doğrusal olmayan analizler ile belirleyip, bu analizlerin bu tür katlı binalar için etkinlik ve doğruluklarını değerlendirmektir. İki boyutlu, değişik kat ve açıklık sayısına sahip analitik modeller, değişken hasar seviyeleri ve ilk kat yükseklikleri dikkate alınarak artımsal itme ve zaman tanım alanında doğrusal olmayan analiz yöntemleriyle incelenmiştir. Özet olarak, yapılan incelemeler (a) Sonlu elemanlar yöntemi kullanarak Türk yapı stoğunu temsil eden modeller oluşturmak, (b) elemanların doğrusal olmayan davranışlarını belirlemek, (c) bu modeller üzerinde doğrusal olmayan analizler yürütmek, ve son olarak (d) bu analizlerin sonuçlarını değerlendirmek şeklindedir. Bu analizlerin sonucunda, yumuşak kat düzensizliği incelenerek bu düzensizliğin sebep ve sonuçları detaylı bir şekilde açıklanmıştır. Bunlara ilaveten değişik yönetmeliklerdeki yumuşak kat düzensizliği tanımları değerlendirilmiş ve ilgili yönetmeliklerdeki bu düzensizliğe sahip yapıların tasarımında uyulması gereken kurallar özetlenmiştir.